E.g.f.: exp(1/((1+x)*(1+x^2)*(1+x^3)) - 1).

Terms

a(0) =1a(1) =-1a(2) =1a(3) =-7a(4) =73a(5) =-421a(6) =2641a(7) =-32131a(8) =403537a(9) =-4527433a(10) =57723841a(11) =-902025631a(12) =15198774361a(13) =-258241785517