Expansion of Product_{m>=1} (1+x^m)^20.

Terms

a(0) =1a(1) =20a(2) =210a(3) =1560a(4) =9255a(5) =46724a(6) =208510a(7) =843320a(8) =3145855a(9) =10963160a(10) =36042250a(11) =112633760a(12) =336622160a(13) =966897820a(14) =2680139300a(15) =7193849624a(16) =18752326235a(17) =47590579080a(18) =117840608100a(19) =285228791880a(20) =675978772326