A242744 - OEIS

%I #8 Mar 13 2020 08:36:58

%S 3,4,3,4,3,6,4,4,5,10,6,6,4,10,8,16,9,18,6,10,11,6,4,12,13,6,5,12,15,

%T 30,9,16,17,12,18,18,12,26,6,40,21,42,22,22,12,16,6,42,16,12,26,52,27,

%U 44,18,6,12,58,30,30,31,12,12,10,33,66,22,16,35,70,36,36,37,18,38,66,9,78,12,12,41,82,16,42,28,58,44,30,12,18,30,46

%N Least number k > 2 such that (k!-n)/(k-n) is an integer.

%C For n > 4, a(2n+1) <= 2n and a(2n) <= n.

%H Jinyuan Wang, <a href="/A242744/b242744.txt">Table of n, a(n) for n = 2..1000</a>

%e (6!-3)/(6-3) = 717/3 = 239 is an integer. Thus a(6) = 3.

%o (PARI) a(n) = if(n==3, 4, for(k=3, oo, if((k!-n)%(k-n)==0, return(k)))); \\ Modified by _Jinyuan Wang_, Mar 13 2020

%K nonn

%O 2,1

%A _Derek Orr_, May 21 2014