G.f.: 1 + Sum_{n>=1} a(n)*x^n/(1 - x^n) = Product_{n>=1} 1/(1 - n*x^n).

Terms

a(0) =1a(1) =2a(2) =5a(3) =11a(4) =24a(5) =48a(6) =96a(7) =184a(8) =348a(9) =645a(10) =1169a(11) =2140a(12) =3761a(13) =6687a(14) =11645a(15) =20326a(16) =34635a(17) =59854a(18) =100579a(19) =171211a(20) =285718a(21) =479325a(22) =791315a(23) =1318955a(24) =2156805a(25) =3553589a(26) =5783306a(27) =9445861a(28) =15250215a(29) =24759156