a(n) = 11^n - 6^n.

Terms

a(0) =0a(1) =5a(2) =85a(3) =1115a(4) =13345a(5) =153275a(6) =1724905a(7) =19207235a(8) =212679265a(9) =2347869995a(10) =25876958425a(11) =284948873555