G.f.: exp( Sum_{n>=1} A020696(n)/2 * x^n/n ), where A020696(n) = Product_{d|n} (d + 1).

Terms

a(0) =1a(1) =1a(2) =2a(3) =3a(4) =7a(5) =9a(6) =27a(7) =33a(8) =73a(9) =100a(10) =203a(11) =269a(12) =987a(13) =1163a(14) =2283a(15) =3234a(16) =6706a(17) =8812a(18) =21455a(19) =27211a(20) =55718a(21) =76055a(22) =147048a(23) =196483a(24) =533149a(25) =659549a(26) =1262531a(27) =1759301a(28) =3462333a(29) =4593487