Expansion of Product_{k>=1} (1 - x^(18*k)) * (1 - x^(18*k-9)) * (1 + x^k) / (1 - x^k).

Terms

a(0) =1a(1) =2a(2) =4a(3) =8a(4) =14a(5) =24a(6) =40a(7) =64a(8) =100a(9) =153a(10) =230a(11) =340a(12) =496a(13) =714a(14) =1016a(15) =1432a(16) =1998a(17) =2764a(18) =3793a(19) =5166a(20) =6988a(21) =9392a(22) =12546a(23) =16664a(24) =22016a(25) =28940a(26) =37860a(27) =49306a(28) =63936a(29) =82568