a(n) = 11^n - 7^n + 1.

Terms

a(0) =1a(1) =5a(2) =73a(3) =989a(4) =12241a(5) =144245a(6) =1653913a(7) =18663629a(8) =208594081a(9) =2317594085a(10) =25654949353a(11) =283334343869