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

Terms

a(0) =1a(1) =20a(2) =250a(3) =2400a(4) =19375a(5) =137604a(6) =884430a(7) =5241000a(8) =29017815a(9) =151597440a(10) =752997538a(11) =3577442200a(12) =16335561280a(13) =71979549460a(14) =307075300540