E.g.f.: exp(x/(1+x)).

Terms

a(0) =1a(1) =1a(2) =-1a(3) =1a(4) =1a(5) =-19a(6) =151a(7) =-1091a(8) =7841a(9) =-56519a(10) =396271a(11) =-2442439a(12) =7701409a(13) =145269541a(14) =-4833158329a(15) =104056218421