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%I #15 Sep 08 2022 08:45:50
%S 5,5,9,25,97,481,2881,20161,161281,1451521,14515201,159667201,
%T 1916006401,24908083201,348713164801,5230697472001,83691159552001,
%U 1422749712384001,25609494822912001,486580401635328001,9731608032706560001,204363768686837760001
%N 4*n! + 1.
%H Vincenzo Librandi, <a href="/A173322/b173322.txt">Table of n, a(n) for n = 0..200</a>
%F a(0) = 5, a(n) = n*a(n-1)-n+1. - _Sergei N. Gladkovskii_, Jul 04 2012
%p a:= proc(n) if n=0 then 5 else a(n) := n*a(n-1)-n+1 fi end: seq (a(n), n=0..25); # _Sergei N. Gladkovskii_, Jul 04 2012
%t 4*Range[0,20]!+1 (* _Harvey P. Dale_, Jun 26 2012 *)
%t Table[4 n! + 1, {n, 0, 21}] (* _Vincenzo Librandi_, Sep 29 2013 *)
%o (Magma) [4*Factorial(n) + 1: n in [0..25]]; /* or */ [5] cat [n eq 1 select n+4 else n*Self(n-1)-n+1: n in [1..25] ]; // _Vincenzo Librandi_, Sep 29 2013
%Y Cf. sequences of the type k*n!+1: A038507 (k=1), A052898 (k=2), A173324 (k=3), this sequence, A173319 (k=5), A173314 (k=6).
%K nonn,easy
%O 0,1
%A _Vincenzo Librandi_, Feb 16 2010