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

Terms

a(0) =1a(1) =20a(2) =230a(3) =2000a(4) =14485a(5) =91804a(6) =524710a(7) =2758520a(8) =13526430a(9) =62505180a(10) =274345784a(11) =1150868440a(12) =4637343915a(13) =18022311520a(14) =67785066390a(15) =247453832688a(16) =878947211030