A133566 * A000244.

Terms

a(0) =1a(1) =3a(2) =12a(3) =27a(4) =108a(5) =243a(6) =972a(7) =2187a(8) =8748a(9) =19683a(10) =78732a(11) =177147a(12) =708588a(13) =1594323a(14) =6377292a(15) =14348907a(16) =57395628a(17) =129140163a(18) =516560652a(19) =1162261467a(20) =4649045868a(21) =10460353203a(22) =41841412812a(23) =94143178827a(24) =376572715308a(25) =847288609443