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

Terms

a(0) =1a(1) =8a(2) =72a(3) =622a(4) =5318a(5) =45417a(6) =387852a(7) =3312153a(8) =28284912a(9) =241545633a(10) =2062735514a(11) =17615213065a(12) =150429237853