Expansion of Product_{m>=1} (1 + m*q^m)^13.

Terms

a(0) =1a(1) =13a(2) =104a(3) =663a(4) =3614a(5) =17576a(6) =78299a(7) =324766a(8) =1269242a(9) =4715204a(10) =16762551a(11) =57327556a(12) =189418658a(13) =606787572a(14) =1890046210a(15) =5738539729a(16) =17019191579a(17) =49394158541a(18) =140507716414a(19) =392299039821