{"group":{"id":1,"name":"Community","lockable":false,"created_at":"2012-01-18T18:02:15.000Z","updated_at":"2026-06-05T00:10:21.000Z","description":"Problems submitted by members of the MATLAB Central community.","is_default":true,"created_by":161519,"badge_id":null,"featured":false,"trending":false,"solution_count_in_trending_period":0,"trending_last_calculated":"2026-06-05T00:00:00.000Z","image_id":null,"published":true,"community_created":false,"status_id":2,"is_default_group_for_player":false,"deleted_by":null,"deleted_at":null,"restored_by":null,"restored_at":null,"description_opc":null,"description_html":null,"published_at":null},"problems":[{"id":44705,"title":"Expand 10^n to Powers of 4","description":"Given an integer n, return the coefficients \r\n\r\n     c = [c_n,c_n-1,...,c_0]\r\n\r\nSuch that\r\n\r\n    10^n = c_n*4^(n) + c_n-1*4^(n-1) +...+ c_0*4^(0)\r\n\r\nWith the constraint that\r\n\r\n   c_n = c_0\r\n\r\nFor example,\r\n\r\n  n = 1\r\n10^n = 10 = 2*4^(1) + 2*4^(0), so c = [2  2] \r\n","description_html":"\u003cp\u003eGiven an integer n, return the coefficients\u003c/p\u003e\u003cpre\u003e     c = [c_n,c_n-1,...,c_0]\u003c/pre\u003e\u003cp\u003eSuch that\u003c/p\u003e\u003cpre\u003e    10^n = c_n*4^(n) + c_n-1*4^(n-1) +...+ c_0*4^(0)\u003c/pre\u003e\u003cp\u003eWith the constraint that\u003c/p\u003e\u003cpre\u003e   c_n = c_0\u003c/pre\u003e\u003cp\u003eFor example,\u003c/p\u003e\u003cpre class=\"language-matlab\"\u003en = 1\r\n10^n = 10 = 2*4^(1) + 2*4^(0), so c = [2  2] \r\n\u003c/pre\u003e","function_template":"function ans = ten2pow4(n)\r\n  \r\nend","test_suite":"%%\r\nn = 0;\r\ncoeff = ten2pow4(n);\r\nassert(isequal(dot(coeff, 4.^flip(0:n)),10^n) \u0026 isequal(coeff(1),coeff(end)) \u0026 coeff(1)\u003e0)\r\n\r\n%%\r\nn = 1;\r\ncoeff = ten2pow4(n);\r\nassert(isequal(dot(coeff, 4.^flip(0:n)),10^n) \u0026 isequal(coeff(1),coeff(end)) \u0026 coeff(1)\u003e0)\r\n\r\n%%\r\nn = 2;\r\ncoeff = ten2pow4(n);\r\nassert(isequal(dot(coeff, 4.^flip(0:n)),10^n) \u0026 isequal(coeff(1),coeff(end)) \u0026 coeff(1)\u003e0)\r\n\r\n%%\r\nn = 3;\r\ncoeff = ten2pow4(n);\r\nassert(isequal(dot(coeff, 4.^flip(0:n)),10^n) \u0026 isequal(coeff(1),coeff(end)) \u0026 coeff(1)\u003e0)\r\n\r\n%%\r\nn = 4;\r\ncoeff = ten2pow4(n);\r\nassert(isequal(dot(coeff, 4.^flip(0:n)),10^n) \u0026 isequal(coeff(1),coeff(end)) \u0026 coeff(1)\u003e0)\r\n\r\n%%\r\nn = 5;\r\ncoeff = ten2pow4(n);\r\nassert(isequal(dot(coeff, 4.^flip(0:n)),10^n) \u0026 isequal(coeff(1),coeff(end)) \u0026 coeff(1)\u003e0)\r\n\r\n%%\r\nn = 6;\r\ncoeff = ten2pow4(n);\r\nassert(isequal(dot(coeff, 4.^flip(0:n)),10^n)\u0026 isequal(coeff(1),coeff(end)) \u0026 coeff(1)\u003e0)\r\n\r\n%%\r\nn = 7;\r\ncoeff = ten2pow4(n);\r\nassert(isequal(dot(coeff, 4.^flip(0:n)),10^n) \u0026 isequal(coeff(1),coeff(end)) \u0026 coeff(1)\u003e0)\r\n\r\n%%\r\nn = 8;\r\ncoeff = ten2pow4(n);\r\nassert(isequal(dot(coeff, 4.^flip(0:n)),10^n) \u0026 isequal(coeff(1),coeff(end)) \u0026 coeff(1)\u003e0)\r\n\r\n%%\r\nn = 9;\r\ncoeff = ten2pow4(n);\r\nassert(isequal(dot(coeff, 4.^flip(0:n)),10^n) \u0026 isequal(coeff(1),coeff(end)) \u0026 coeff(1)\u003e0)\r\n\r\n%%\r\nn = 10;\r\ncoeff = ten2pow4(n);\r\nassert(isequal(dot(coeff, 4.^flip(0:n)),10^n) \u0026 isequal(coeff(1),coeff(end))\u0026coeff(1)\u003e0)\r\n\r\n%%\r\nn = 11;\r\ncoeff = ten2pow4(n);\r\nassert(isequal(dot(coeff, 4.^flip(0:n)),10^n) \u0026 isequal(coeff(1),coeff(end))\u0026coeff(1)\u003e0)\r\n\r\n%%\r\nn = 12;\r\ncoeff = ten2pow4(n);\r\nassert(isequal(dot(coeff, 4.^flip(0:n)),10^n) \u0026 isequal(coeff(1),coeff(end))\u0026coeff(1)\u003e0)\r\n\r\n%%\r\nn = 13;\r\ncoeff = ten2pow4(n);\r\nassert(isequal(dot(coeff, 4.^flip(0:n)),10^n) \u0026 isequal(coeff(1),coeff(end))\u0026coeff(1)\u003e0)\r\n\r\n%%\r\nn = 14;\r\ncoeff = ten2pow4(n);\r\nassert(isequal(dot(coeff, 4.^flip(0:n)),10^n) \u0026 isequal(coeff(1),coeff(end))\u0026coeff(1)\u003e0)\r\n\r\n%%\r\nn = 15;\r\ncoeff = ten2pow4(n);\r\nassert(isequal(dot(coeff, 4.^flip(0:n)),10^n) \u0026 isequal(coeff(1),coeff(end))\u0026coeff(1)\u003e0)\r\n\r\n%%\r\nn = 16;\r\ncoeff = ten2pow4(n);\r\nassert(isequal(dot(coeff, 4.^flip(0:n)),10^n) \u0026 isequal(coeff(1),coeff(end)) \u0026 coeff(1)\u003e0)","published":true,"deleted":false,"likes_count":5,"comments_count":3,"created_by":178544,"edited_by":null,"edited_at":null,"deleted_by":null,"deleted_at":null,"solvers_count":49,"test_suite_updated_at":"2018-08-14T12:07:53.000Z","rescore_all_solutions":false,"group_id":1,"created_at":"2018-08-02T21:15:38.000Z","updated_at":"2026-05-24T13:11:26.000Z","published_at":"2018-08-02T21:19:07.000Z","restored_at":null,"restored_by":null,"spam":false,"simulink":false,"admin_reviewed":false,"description_opc":"{\"relationships\":[{\"relationshipType\":\"http://schemas.mathworks.com/matlab/code/2013/relationships/document\",\"targetMode\":\"\",\"relationshipId\":\"rId1\",\"target\":\"/matlab/document.xml\"},{\"relationshipType\":\"http://schemas.mathworks.com/matlab/code/2013/relationships/output\",\"targetMode\":\"\",\"relationshipId\":\"rId2\",\"target\":\"/matlab/output.xml\"}],\"parts\":[{\"partUri\":\"/matlab/document.xml\",\"relationship\":[],\"contentType\":\"application/vnd.mathworks.matlab.code.document+xml\",\"content\":\"\u003c?xml version=\\\"1.0\\\" encoding=\\\"UTF-8\\\"?\u003e\\n\u003cw:document xmlns:w=\\\"http://schemas.openxmlformats.org/wordprocessingml/2006/main\\\"\u003e\u003cw:body\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"text\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003eGiven an integer n, return the coefficients\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"code\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003e\u003c![CDATA[     c = [c_n,c_n-1,...,c_0]]]\u003e\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"text\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003eSuch that\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"code\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003e\u003c![CDATA[    10^n = c_n*4^(n) + c_n-1*4^(n-1) +...+ c_0*4^(0)]]\u003e\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"text\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003eWith the constraint that\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"code\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003e\u003c![CDATA[   c_n = c_0]]\u003e\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"text\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003eFor example,\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"code\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003e\u003c![CDATA[n = 1\\n10^n = 10 = 2*4^(1) + 2*4^(0), so c = [2  2]]]\u003e\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003c/w:body\u003e\u003c/w:document\u003e\"},{\"partUri\":\"/matlab/output.xml\",\"contentType\":\"text/xml\",\"content\":\"\u003c?xml version=\\\"1.0\\\" encoding=\\\"UTF-8\\\" standalone=\\\"no\\\" ?\u003e\u003cembeddedOutputs\u003e\u003cmetaData\u003e\u003cevaluationState\u003emanual\u003c/evaluationState\u003e\u003clayoutState\u003ecode\u003c/layoutState\u003e\u003coutputStatus\u003eready\u003c/outputStatus\u003e\u003c/metaData\u003e\u003coutputArray type=\\\"array\\\"/\u003e\u003cregionArray type=\\\"array\\\"/\u003e\u003c/embeddedOutputs\u003e\"}]}"}],"problem_search":{"problems":[{"id":44705,"title":"Expand 10^n to Powers of 4","description":"Given an integer n, return the coefficients \r\n\r\n     c = [c_n,c_n-1,...,c_0]\r\n\r\nSuch that\r\n\r\n    10^n = c_n*4^(n) + c_n-1*4^(n-1) +...+ c_0*4^(0)\r\n\r\nWith the constraint that\r\n\r\n   c_n = c_0\r\n\r\nFor example,\r\n\r\n  n = 1\r\n10^n = 10 = 2*4^(1) + 2*4^(0), so c = [2  2] \r\n","description_html":"\u003cp\u003eGiven an integer n, return the coefficients\u003c/p\u003e\u003cpre\u003e     c = [c_n,c_n-1,...,c_0]\u003c/pre\u003e\u003cp\u003eSuch that\u003c/p\u003e\u003cpre\u003e    10^n = c_n*4^(n) + c_n-1*4^(n-1) +...+ c_0*4^(0)\u003c/pre\u003e\u003cp\u003eWith the constraint that\u003c/p\u003e\u003cpre\u003e   c_n = c_0\u003c/pre\u003e\u003cp\u003eFor example,\u003c/p\u003e\u003cpre class=\"language-matlab\"\u003en = 1\r\n10^n = 10 = 2*4^(1) + 2*4^(0), so c = [2  2] \r\n\u003c/pre\u003e","function_template":"function ans = ten2pow4(n)\r\n  \r\nend","test_suite":"%%\r\nn = 0;\r\ncoeff = ten2pow4(n);\r\nassert(isequal(dot(coeff, 4.^flip(0:n)),10^n) \u0026 isequal(coeff(1),coeff(end)) \u0026 coeff(1)\u003e0)\r\n\r\n%%\r\nn = 1;\r\ncoeff = ten2pow4(n);\r\nassert(isequal(dot(coeff, 4.^flip(0:n)),10^n) \u0026 isequal(coeff(1),coeff(end)) \u0026 coeff(1)\u003e0)\r\n\r\n%%\r\nn = 2;\r\ncoeff = ten2pow4(n);\r\nassert(isequal(dot(coeff, 4.^flip(0:n)),10^n) \u0026 isequal(coeff(1),coeff(end)) \u0026 coeff(1)\u003e0)\r\n\r\n%%\r\nn = 3;\r\ncoeff = ten2pow4(n);\r\nassert(isequal(dot(coeff, 4.^flip(0:n)),10^n) \u0026 isequal(coeff(1),coeff(end)) \u0026 coeff(1)\u003e0)\r\n\r\n%%\r\nn = 4;\r\ncoeff = ten2pow4(n);\r\nassert(isequal(dot(coeff, 4.^flip(0:n)),10^n) \u0026 isequal(coeff(1),coeff(end)) \u0026 coeff(1)\u003e0)\r\n\r\n%%\r\nn = 5;\r\ncoeff = ten2pow4(n);\r\nassert(isequal(dot(coeff, 4.^flip(0:n)),10^n) \u0026 isequal(coeff(1),coeff(end)) \u0026 coeff(1)\u003e0)\r\n\r\n%%\r\nn = 6;\r\ncoeff = ten2pow4(n);\r\nassert(isequal(dot(coeff, 4.^flip(0:n)),10^n)\u0026 isequal(coeff(1),coeff(end)) \u0026 coeff(1)\u003e0)\r\n\r\n%%\r\nn = 7;\r\ncoeff = ten2pow4(n);\r\nassert(isequal(dot(coeff, 4.^flip(0:n)),10^n) \u0026 isequal(coeff(1),coeff(end)) \u0026 coeff(1)\u003e0)\r\n\r\n%%\r\nn = 8;\r\ncoeff = ten2pow4(n);\r\nassert(isequal(dot(coeff, 4.^flip(0:n)),10^n) \u0026 isequal(coeff(1),coeff(end)) \u0026 coeff(1)\u003e0)\r\n\r\n%%\r\nn = 9;\r\ncoeff = ten2pow4(n);\r\nassert(isequal(dot(coeff, 4.^flip(0:n)),10^n) \u0026 isequal(coeff(1),coeff(end)) \u0026 coeff(1)\u003e0)\r\n\r\n%%\r\nn = 10;\r\ncoeff = ten2pow4(n);\r\nassert(isequal(dot(coeff, 4.^flip(0:n)),10^n) \u0026 isequal(coeff(1),coeff(end))\u0026coeff(1)\u003e0)\r\n\r\n%%\r\nn = 11;\r\ncoeff = ten2pow4(n);\r\nassert(isequal(dot(coeff, 4.^flip(0:n)),10^n) \u0026 isequal(coeff(1),coeff(end))\u0026coeff(1)\u003e0)\r\n\r\n%%\r\nn = 12;\r\ncoeff = ten2pow4(n);\r\nassert(isequal(dot(coeff, 4.^flip(0:n)),10^n) \u0026 isequal(coeff(1),coeff(end))\u0026coeff(1)\u003e0)\r\n\r\n%%\r\nn = 13;\r\ncoeff = ten2pow4(n);\r\nassert(isequal(dot(coeff, 4.^flip(0:n)),10^n) \u0026 isequal(coeff(1),coeff(end))\u0026coeff(1)\u003e0)\r\n\r\n%%\r\nn = 14;\r\ncoeff = ten2pow4(n);\r\nassert(isequal(dot(coeff, 4.^flip(0:n)),10^n) \u0026 isequal(coeff(1),coeff(end))\u0026coeff(1)\u003e0)\r\n\r\n%%\r\nn = 15;\r\ncoeff = ten2pow4(n);\r\nassert(isequal(dot(coeff, 4.^flip(0:n)),10^n) \u0026 isequal(coeff(1),coeff(end))\u0026coeff(1)\u003e0)\r\n\r\n%%\r\nn = 16;\r\ncoeff = ten2pow4(n);\r\nassert(isequal(dot(coeff, 4.^flip(0:n)),10^n) \u0026 isequal(coeff(1),coeff(end)) \u0026 coeff(1)\u003e0)","published":true,"deleted":false,"likes_count":5,"comments_count":3,"created_by":178544,"edited_by":null,"edited_at":null,"deleted_by":null,"deleted_at":null,"solvers_count":49,"test_suite_updated_at":"2018-08-14T12:07:53.000Z","rescore_all_solutions":false,"group_id":1,"created_at":"2018-08-02T21:15:38.000Z","updated_at":"2026-05-24T13:11:26.000Z","published_at":"2018-08-02T21:19:07.000Z","restored_at":null,"restored_by":null,"spam":false,"simulink":false,"admin_reviewed":false,"description_opc":"{\"relationships\":[{\"relationshipType\":\"http://schemas.mathworks.com/matlab/code/2013/relationships/document\",\"targetMode\":\"\",\"relationshipId\":\"rId1\",\"target\":\"/matlab/document.xml\"},{\"relationshipType\":\"http://schemas.mathworks.com/matlab/code/2013/relationships/output\",\"targetMode\":\"\",\"relationshipId\":\"rId2\",\"target\":\"/matlab/output.xml\"}],\"parts\":[{\"partUri\":\"/matlab/document.xml\",\"relationship\":[],\"contentType\":\"application/vnd.mathworks.matlab.code.document+xml\",\"content\":\"\u003c?xml version=\\\"1.0\\\" encoding=\\\"UTF-8\\\"?\u003e\\n\u003cw:document xmlns:w=\\\"http://schemas.openxmlformats.org/wordprocessingml/2006/main\\\"\u003e\u003cw:body\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"text\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003eGiven an integer n, return the coefficients\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"code\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003e\u003c![CDATA[     c = [c_n,c_n-1,...,c_0]]]\u003e\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"text\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003eSuch that\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"code\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003e\u003c![CDATA[    10^n = c_n*4^(n) + c_n-1*4^(n-1) +...+ c_0*4^(0)]]\u003e\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"text\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003eWith the constraint that\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"code\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003e\u003c![CDATA[   c_n = c_0]]\u003e\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"text\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003eFor example,\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003cw:p\u003e\u003cw:pPr\u003e\u003cw:pStyle w:val=\\\"code\\\"/\u003e\u003c/w:pPr\u003e\u003cw:r\u003e\u003cw:t\u003e\u003c![CDATA[n = 1\\n10^n = 10 = 2*4^(1) + 2*4^(0), so c = [2  2]]]\u003e\u003c/w:t\u003e\u003c/w:r\u003e\u003c/w:p\u003e\u003c/w:body\u003e\u003c/w:document\u003e\"},{\"partUri\":\"/matlab/output.xml\",\"contentType\":\"text/xml\",\"content\":\"\u003c?xml version=\\\"1.0\\\" encoding=\\\"UTF-8\\\" standalone=\\\"no\\\" ?\u003e\u003cembeddedOutputs\u003e\u003cmetaData\u003e\u003cevaluationState\u003emanual\u003c/evaluationState\u003e\u003clayoutState\u003ecode\u003c/layoutState\u003e\u003coutputStatus\u003eready\u003c/outputStatus\u003e\u003c/metaData\u003e\u003coutputArray type=\\\"array\\\"/\u003e\u003cregionArray type=\\\"array\\\"/\u003e\u003c/embeddedOutputs\u003e\"}]}"}],"errors":[],"facets":[[{"value":"Number Manipulation IV","count":1,"selected":false}],[{"value":"medium","count":1,"selected":false}]],"term":"tag:\"number triangle\"","page":1,"per_page":50,"sort":"map(difficulty_value,0,0,999) asc"}}