The OEIS is supported by the many generous donors to the OEIS Foundation.
%I #6 Jan 20 2013 13:57:57
%S 1,2,6,26,131,791,5543,44348,399139,3991392,43905314,526863779,
%T 6849229138,95889207938,1438338119083,23013409905337,391227968390730,
%U 7042103431033155,133799965189629948,2675999303792598976
%N [ exp(2/21)*n! ].
%t With[{c=Exp[2/21]},Floor[c*Range[20]!]] (* _Harvey P. Dale_, Jan 20 2013 *)
%K nonn
%O 1,2
%A _Simon Plouffe_