|
%I #14 Jun 18 2021 02:39:01
%S 1,1,1,3,12,59,352,2455,19592,176033,1758218,19323213,231721820,
%T 3010799363,42133608902,631791578187,10105884589152,171760897623865,
%U 3091106286704942,58721542573721093,1174269157320995428
%N a(0) = 1; a(1) = 1; a(2) = 1; a(n) = (n-1)*a(n-1) + (n-2)*a(n-2) + (n-3)*a(n-3) for n >= 3.
%p a[0]:=1: a[1]:=1: a[2]:=1: for n from 3 to 20 do a[n]:=(n-1)*a[n-1]+(n-2)*a[n-2]+(n-3)*a[n-3] od: seq(a[n],n=0..20);
%t a[0] = 1; a[1] = 1; a[2] = 1; a[n_] := a[n] = (n - 1)*a[n - 1] + (n - 2)*a[n - 2] + (n - 3)*a[n - 3] Table[a[n], {n, 0, 50}]
%t RecurrenceTable[{a[0]==a[1]==a[2]==1,a[n]==(n-1)a[n-1]+(n-2)a[n-2]+ (n-3)a[n-3]},a,{n,50}] (* _Harvey P. Dale_, Jul 10 2012 *)
%K nonn,easy
%O 0,4
%A _Roger L. Bagula_, Sep 21 2006
%E Edited by _N. J. A. Sloane_, Oct 08 2006
%E Offset changed to 0 by _Georg Fischer_, Jun 18 2021
|
