E.g.f.: Product_{k>0} (1-k*x^k)^(1/k).

Terms

a(0) =1a(1) =-1a(2) =-2a(3) =0a(4) =-12a(5) =180a(6) =-1080a(7) =15120a(8) =-45360a(9) =-15120a(10) =6501600a(11) =166320000a(12) =-6017457600a(13) =73297224000a(14) =724669545600