a(n) = floor(exp(7/24)*n!).

Terms

a(0) =1a(1) =2a(2) =8a(3) =32a(4) =160a(5) =963a(6) =6746a(7) =53974a(8) =485771a(9) =4857717a(10) =53434892a(11) =641218712a(12) =8335843266a(13) =116701805732