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Smallest positive integer m such that n divides [7^m/m] (=A129797(m)).
9

%I #9 May 23 2023 23:09:33

%S 1,2,2,2,4,2,1,2,13,4,20,2,12,11,4,11,16,13,3,4,11,20,67,2,4,12,19,11,

%T 43,4,60,13,20,16,13,13,9,3,12,4,10,11,6,20,13,67,66,11,7,4,16,12,79,

%U 19,20,11,3,43,78,4,51,60,13,17,12,20,75,16,67,13,52,13,24,9,4,6,31,12,35

%N Smallest positive integer m such that n divides [7^m/m] (=A129797(m)).

%C This sequence is well-defined.

%H Harvey P. Dale, <a href="/A138260/b138260.txt">Table of n, a(n) for n = 1..1000</a>

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

%t spi[n_]:=Module[{m=1},While[Mod[Floor[7^m/m],n]!=0,m++];m]; Array[spi,80] (* _Harvey P. Dale_, Aug 16 2018 *)

%Y Cf. A129797, A138255, A138256, A138257, A138258, A138259, A138261, A138262, A138263.

%K nonn

%O 1,2

%A _Max Alekseyev_, Mar 09 2008.