a(n) = ceiling((Pi^n)*(e^n)).

Terms

a(0) =9a(1) =73a(2) =623a(3) =5319a(4) =45418a(5) =387853a(6) =3312154a(7) =28284913a(8) =241545634a(9) =2062735515a(10) =17615213066a(11) =150429237854