a(n) = floor( n! / e ).

Terms

a(0) =0a(1) =0a(2) =2a(3) =8a(4) =44a(5) =264a(6) =1854a(7) =14832a(8) =133496a(9) =1334960a(10) =14684570a(11) =176214840a(12) =2290792932a(13) =32071101048a(14) =481066515734