Floor( exp(3/14)*n! ).

Terms

a(0) =1a(1) =2a(2) =7a(3) =29a(4) =148a(5) =892a(6) =6244a(7) =49955a(8) =449599a(9) =4495998a(10) =49455981a(11) =593471772a(12) =7715133043a(13) =108011862610