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

Terms

a(0) =1a(1) =1a(2) =2a(3) =5a(4) =13a(5) =32a(6) =82a(7) =201a(8) =498a(9) =1214a(10) =2954a(11) =7117a(12) =17115a(13) =40880a(14) =97336a(15) =230699a(16) =545068a(17) =1283150a(18) =3011783a(19) =7047353a(20) =16445814a(21) =38275172a(22) =88859213a(23) =205796476a(24) =475539242a(25) =1096428621a(26) =2522704211a(27) =5792637135a(28) =13275381694a(29) =30367439045