%I #15 May 15 2017 16:04:54
%S 1,1,1,3,9,45,265,1855,14833,133497,1334961,14684571,176214841,
%T 2290792933,32071101049,481066515735,7697064251745,130850092279665,
%U 2355301661033953,44750731559645107,895014631192902121,18795307255050944541,413496759611120779881
%N a(n) = ceiling(n!/e) with e = A001113 = exp(1).
%D F. S. Roberts, Applied Combinatorics, Prentice-Hall, 1984, p. 263.
%F a(2n) = A000166(2n). a(2n+1) = A000166(2n+1)+1.
%t Table[Ceiling[n!*Exp[ -1]], {n, 0, 30}]
%o (PARI) a(n) = ceil(n!/exp(1)); \\ _Michel Marcus_, May 15 2017
%Y Cf. A000166.
%K nonn
%O 0,4
%A _Roger L. Bagula_, Mar 15 2010