a(n) = numerator(Sum_{k=1..n} k^2/k!).

Terms

a(0) =0a(1) =1a(2) =3a(3) =9a(4) =31a(5) =43a(6) =217a(7) =3913a(8) =9133a(9) =73067a(10) =1972819a(11) =6576067a(12) =24112247a(13) =372017527a(14) =1612075951a(15) =157983443203