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

Terms

a(0) =1a(1) =2a(2) =3a(3) =6a(4) =9a(5) =12a(6) =20a(7) =28a(8) =36a(9) =52a(10) =70a(11) =88a(12) =120a(13) =156a(14) =192a(15) =250a(16) =318a(17) =386a(18) =488a(19) =606a(20) =727a(21) =900a(22) =1101a(23) =1308a(24) =1590a(25) =1916a(26) =2257a(27) =2706a(28) =3225a(29) =3768