Expansion of Product_{k>=1} (1 + x^k)^(k*(2*k-1)).

Terms

a(0) =1a(1) =1a(2) =6a(3) =21a(4) =58a(5) =178a(6) =494a(7) =1365a(8) =3640a(9) =9533a(10) =24401a(11) =61384a(12) =151958a(13) =370335a(14) =890565a(15) =2113913a(16) =4959199a(17) =11505799a(18) =26420628a(19) =60082005a(20) =135386341a(21) =302448477a(22) =670148898a(23) =1473387787a(24) =3215519032a(25) =6968266907a(26) =14999453058a(27) =32079714584a(28) =68187859040a(29) =144083404856