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A138258 Smallest positive integer m such that n divides [5^m/m] (=A129795(m)). 9

%I #14 May 23 2023 23:08:54

%S 1,2,2,2,1,2,6,7,7,7,22,2,4,6,7,13,16,7,10,7,6,31,55,7,5,4,19,6,15,7,

%T 6,17,31,16,13,7,36,10,4,7,3,6,42,31,7,55,51,13,43,26,16,4,52,19,31,

%U 13,18,15,27,7,31,6,13,17,17,31,9,16,67,13,11,7,66,36,26,18,31,4,9,13,56,61

%N Smallest positive integer m such that n divides [5^m/m] (=A129795(m)).

%C This sequence is well-defined.

%H Robert Israel, <a href="/A138258/b138258.txt">Table of n, a(n) for n = 1..10000</a>

%H Romanian Master in Mathematics Contest, <a href="https://artofproblemsolving.com/community/c6h187665">Problem 3</a>, Bucharest, 2007.

%p N:= 100: # for a(1)..a(N)

%p V:= Vector(N):

%p count:= 0: missing:= {$1..N}:

%p Q:= ilcm(seq(i,i=1..N)):

%p for m from 1 while count < N do

%p v:= floor(5^m/m);

%p r:= igcd(v,Q);

%p d:= select(t -> r mod t = 0, missing);

%p missing:= missing minus d;

%p count:= count+nops(d);

%p V[convert(d,list)]:= m;

%p od:

%p convert(V,list); # _Robert Israel_, Aug 27 2020

%Y Cf. A129795, A138255, A138256, A138257, A138259, A138260, A138261, A138262, A138263.

%K nonn

%O 1,2

%A _Max Alekseyev_, Mar 09 2008

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Last modified April 19 14:10 EDT 2024. Contains 371792 sequences. (Running on oeis4.)