Dirichlet convolution of b_n=2^(n-1) with Bell numbers.

Terms

a(0) =1a(1) =3a(2) =6a(3) =15a(4) =31a(5) =92a(6) =267a(7) =1023a(8) =4404a(9) =21705a(10) =116999a(11) =680790a(12) =4217693a(13) =27653099a(14) =190915798a(15) =1382993235a(16) =10480207683a(17) =82865009684a(18) =682077068303