Denominator of Sum_{k=0..n} (-1)^k/k!.

Terms

a(0) =1a(1) =1a(2) =2a(3) =3a(4) =8a(5) =30a(6) =144a(7) =280a(8) =5760a(9) =45360a(10) =44800a(11) =3991680a(12) =43545600a(13) =172972800a(14) =6706022400a(15) =93405312000a(16) =42268262400