Problem 1642. BULLSEYE Part 2: Reference Problem 18 BULLSEYE

Given n (always odd), return output a that has concentric rings of the 1s and 0s around the center point. Examples:

 Input  n = 3
 Output a is [ 1 1 1 
               1 0 1
               1 1 1 ]

 Input  n = 5
 Output a is [    1     1     1     1     1
                  1     0     0     0     1
                  1     0     1     0     1
                  1     0     0     0     1
                  1     1     1     1     1]