a(n) = 3^n + Fibonacci(n).

Terms

a(0) =1a(1) =4a(2) =10a(3) =29a(4) =84a(5) =248a(6) =737a(7) =2200a(8) =6582a(9) =19717a(10) =59104a(11) =177236a(12) =531585a(13) =1594556a(14) =4783346a(15) =14349517a(16) =43047708a(17) =129141760a(18) =387423073a(19) =1162265648a(20) =3486791166a(21) =10460364149a(22) =31381077320a(23) =94143207484a(24) =282429582849a(25) =847288684468