Expansion of 1 / (1 - Sum_{i>=1, j>=1} x^(i*(j + 1))).

Terms

a(0) =1a(1) =0a(2) =1a(3) =1a(4) =3a(5) =3a(6) =9a(7) =10a(8) =25a(9) =34a(10) =72a(11) =106a(12) =215a(13) =330a(14) =635a(15) =1025a(16) =1899a(17) =3141a(18) =5713a(19) =9602a(20) =17213a(21) =29292a(22) =51982a(23) =89149a(24) =157249a(25) =271027a(26) =476037a(27) =823386a(28) =1442063a(29) =2500015