Product_{n>=1} (1 + a(n) * x^n) = 1 + Sum_{n>=1} (n * (n + 1) / 2) * x^n.

Terms

a(0) =1a(1) =3a(2) =3a(3) =7a(4) =-1a(5) =-8a(6) =-3a(7) =48a(8) =1a(9) =-39a(10) =-6a(11) =34a(12) =-25a(13) =-293a(14) =24a(15) =2649a(16) =-35a(17) =-2104a(18) =-239a(19) =3387a(20) =323a(21) =-15322a(22) =-182a(23) =27551a(24) =-2477a(25) =-121985a(26) =3663a(27) =275053a(28) =-360a(29) =-942231