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

Terms

a(0) =1a(1) =-1a(2) =-2a(3) =0a(4) =0a(5) =120a(6) =0a(7) =5040a(8) =0a(9) =0a(10) =0a(11) =0a(12) =-479001600a(13) =0a(14) =0a(16) =0a(17) =0a(18) =0a(19) =0a(20) =0a(21) =0a(23) =0a(24) =0a(25) =0a(27) =0a(28) =0a(29) =0a(30) =0a(31) =0a(32) =0