Expansion of (-1 + Product_{k>=1} 1 / (1 - x^k))^3.

Terms

a(0) =1a(1) =6a(2) =21a(3) =59a(4) =144a(5) =321a(6) =669a(7) =1323a(8) =2511a(9) =4604a(10) =8202a(11) =14253a(12) =24241a(13) =40449a(14) =66363a(15) =107234a(16) =170910a(17) =269004a(18) =418566a(19) =644436a(20) =982536a(21) =1484482a(22) =2223942a(23) =3305484a(24) =4876620a(25) =7144455a(26) =10398123a(27) =15039564a(28) =21624678a(29) =30919323