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

Terms

a(0) =1a(1) =1a(2) =2a(3) =8a(4) =31a(5) =157a(6) =915a(7) =6213a(8) =48240a(9) =423398a(10) =4147775a(11) =44882107a(12) =531564195a(13) =6837784087a(14) =94909482330