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

Terms

a(0) =1a(1) =-1a(2) =0a(3) =0a(4) =-1a(5) =2a(6) =-2a(7) =2a(8) =-1a(9) =-2a(10) =5a(11) =-6a(12) =5a(13) =-1a(14) =-5a(15) =10a(16) =-14a(17) =14a(18) =-5a(19) =-10a(20) =26a(21) =-38a(22) =36a(23) =-15a(24) =-20a(25) =60a(26) =-91a(27) =93a(28) =-51a(29) =-33