G.f.: exp( Sum_{n>=1} (Sum_{d|n} d*x^d)^n/n ).

Terms

a(0) =1a(1) =1a(2) =1a(3) =3a(4) =5a(5) =10a(6) =18a(7) =45a(8) =98a(9) =242a(10) =569a(11) =1360a(12) =3101a(13) =6799a(14) =14674a(15) =31297a(16) =66483a(17) =144954a(18) =326150a(19) =787455a(20) =2019266a(21) =5425240a(22) =14793678a(23) =40049832a(24) =105958990a(25) =272562864a(26) =679336804a(27) =1644951169a(28) =3882700822a(29) =8997217790