a(n) = 5*n + 3^n - 2^n.

Terms

a(0) =0a(1) =6a(2) =15a(3) =34a(4) =85a(5) =236a(6) =695a(7) =2094a(8) =6345a(9) =19216a(10) =58075a(11) =175154a(12) =527405a(13) =1586196a(14) =4766655a(15) =14316214a(16) =42981265a(17) =129009176a(18) =387158435a(19) =1161737274a(20) =3485735925a(21) =10458256156a(22) =31376865415a(23) =94134790334a(24) =282412759385a(25) =847255055136