a(n) = n successive applications of the <*>(3,2) operator to 1.

Terms

a(0) =1a(1) =3a(2) =9a(3) =27a(4) =61a(5) =123a(6) =349a(7) =1007a(8) =2021a(9) =4043a(10) =8089a(11) =16187a(12) =42481a(13) =125363a(14) =271029a(15) =612067a(16) =1234141a(17) =3498383a(18) =10087069a(19) =20254147a(20) =40558401a(21) =81167203a(22) =163394609a(23) =429879827a(24) =1268830461a(25) =2745691323a(26) =6196472949a(27) =12499016807a(28) =35407044421a(29) =101221129243