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

Terms

a(0) =1a(1) =0a(2) =2a(3) =6a(4) =14a(5) =32a(6) =74a(7) =166a(8) =370a(9) =810a(10) =1736a(11) =3682a(12) =7718a(13) =15976a(14) =32754a(15) =66508a(16) =133794a(17) =266948a(18) =528424a(19) =1038178a(20) =2025456a(21) =3925360a(22) =7559298a(23) =14470162a(24) =27540598a(25) =52130440a(26) =98159832a(27) =183905636a(28) =342896254a(29) =636384748