Expansion of Sum_{k>=0} x^(k^2+k)/((1-x)(1-x^2)...(1-x^(2k))).

Terms

a(0) =1a(1) =0a(2) =1a(3) =1a(4) =2a(5) =2a(6) =4a(7) =4a(8) =6a(9) =7a(10) =10a(11) =11a(12) =16a(13) =18a(14) =24a(15) =28a(16) =36a(17) =42a(18) =54a(19) =62a(20) =78a(21) =91a(22) =112a(23) =130a(24) =159a(25) =184a(26) =222a(27) =258a(28) =308a(29) =356