a(n) = 2^n + 3^n + 8^n.

Terms

a(0) =3a(1) =13a(2) =77a(3) =547a(4) =4193a(5) =33043a(6) =262937a(7) =2099467a(8) =16784033a(9) =134237923a(10) =1073801897a(11) =8590113787a(12) =68720012273a(13) =549757416403