%I #2 Mar 31 2012 10:31:22
%S 4,24,620448401733239439360000
%N a(0)=4 and a(n+1)=a(n)!
%C Initializing at 0, 1 or 2 gives constant sequences (except for the first term when initializing at 0).
%C Initializing at 3 gives 3,6,720,720!,...
%Y Cf. A000142 (factorials).
%K bref,nonn
%O 0,1
%A _Benoit Jubin_, Jun 27 2009