Dirichlet convolution of 3^(n-1) with itself.

Terms

a(0) =1a(1) =6a(2) =18a(3) =63a(4) =162a(5) =540a(6) =1458a(7) =4536a(8) =13203a(9) =39852a(10) =118098a(11) =356238a(12) =1062882a(13) =3193020a(14) =9567396a(15) =28711665a(16) =86093442a(17) =258324066a(18) =774840978a(19) =2324645406a(20) =6973581924a(21) =20921060700a(22) =62762119218a(23) =188287473024a(24) =564859079523