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

Terms

a(0) =2a(1) =6a(2) =15a(3) =38a(4) =101a(5) =280a(6) =799a(7) =2322a(8) =6825a(9) =20204a(10) =60083a(11) =179206a(12) =535549a(13) =1602528a(14) =4799367a(15) =14381690a(16) =43112273a(17) =129271252a(18) =387682651a(19) =1162785774a(20) =3487832997a(21) =10462450376a(22) =31385253935a(23) =94151567458a(24) =282446313721a(25) =847322163900