a(n) = [x^n] Product_{k=1..n} (x^(k^3) + 1 + 1/x^(k^3)).

Terms

a(0) =1a(1) =1a(2) =0a(3) =0a(4) =0a(5) =0a(6) =0a(7) =4a(8) =6a(9) =15a(10) =24a(11) =40a(12) =69a(13) =138a(14) =396a(15) =1028a(16) =3062a(17) =8269a(18) =21680a(19) =50955a(20) =115457a(21) =262239a(22) =631393a(23) =1666438a(24) =4558051a(25) =12913587a(26) =35530351a(27) =95825467a(28) =246943968a(29) =628040166