E.g.f.: Product_{m>=0} exp(-x^(4*m+1)).

Terms

a(0) =1a(1) =-1a(2) =1a(3) =-1a(4) =1a(5) =-121a(6) =721a(7) =-2521a(8) =6721a(9) =-378001a(10) =5473441a(11) =-39972241a(12) =199679041a(13) =-7005552841a(14) =176899522801