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

Terms

a(0) =1a(1) =-1a(2) =-1a(3) =1a(4) =2a(5) =26a(6) =-6a(7) =414a(8) =-624a(9) =-288a(10) =-20880a(11) =164880a(12) =-9756000a(13) =43529760a(14) =-324404640a(15) =-4052492640a(16) =-48521410560