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

Terms

a(0) =1a(1) =4a(2) =11a(3) =35a(4) =96a(5) =310a(6) =932a(7) =3106a(8) =10719a(9) =40956a(10) =175024a(11) =856215a(12) =4745038a(13) =29240098a(14) =195682588a(15) =1397312405a(16) =10523188868a(17) =82994029902a(18) =682464226648