a(n) = floor(exp(15/23) * n!).

Terms

a(0) =1a(1) =3a(2) =11a(3) =46a(4) =230a(5) =1382a(6) =9675a(7) =77402a(8) =696624a(9) =6966242a(10) =76628663a(11) =919543959a(12) =11954071471a(13) =167357000594