a(n) = (16^n-3^n)/13.

A180845

a(n) = (16^n-3^n)/13.

Terms

    a(0) =0a(1) =1a(2) =19a(3) =313a(4) =5035a(5) =80641a(6) =1290499a(7) =20648713a(8) =330381595a(9) =5286112081a(10) =84577812979

External references