Numerator of Sum_{k=1..n} (-1)^(k+1)/k!.

Terms

a(0) =0a(1) =1a(2) =1a(3) =2a(4) =5a(5) =19a(6) =91a(7) =177a(8) =3641a(9) =28673a(10) =28319a(11) =2523223a(12) =27526069a(13) =109339663a(14) =4239014627a(15) =59043418019a(16) =26718637649