a(n) = floor( exp(5/11)*n! ).

Terms

a(0) =1a(1) =3a(2) =9a(3) =37a(4) =189a(5) =1134a(6) =7940a(7) =63522a(8) =571701a(9) =5717018a(10) =62887206a(11) =754646473a(12) =9810404152a(13) =137345658132