How to synthesise discrete signal?

How can I synthesise a discrete signal given by the expression x[n]=1.23^(-n) for 0<=n<=819?

Thank you in advance.

Answer 1

[Voss]

n = 0:819;
x = 1.23.^-n;
stem(n,x)
xlim([0 20]) % just look at the beginning

Answer 2

[David Hill]

n=0:.01:819;%not sure what interval or frequency
x=1.23.^(-n);