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

Terms

a(0) =1a(1) =4a(2) =14a(3) =44a(4) =124a(5) =328a(6) =824a(7) =1980a(8) =4590a(9) =10320a(10) =22584a(11) =48268a(12) =101016a(13) =207432a(14) =418704a(15) =832032a(16) =1629764a(17) =3150280a(18) =6014998a(19) =11354084a(20) =21204488a(21) =39206168a(22) =71811256a(23) =130369900a(24) =234704360a(25) =419195412a(26) =743085912a(27) =1307823672a(28) =2286094704a(29) =3970174648