Dirichlet convolution of b_n=1 with Bell numbers.

Terms

a(0) =1a(1) =2a(2) =3a(3) =7a(4) =16a(5) =56a(6) =204a(7) =884a(8) =4143a(9) =21164a(10) =115976a(11) =678631a(12) =4213598a(13) =27644642a(14) =190899340a(15) =1382959429a(16) =10480142148a(17) =82864874000a(18) =682076806160