A138261 - OEIS

%I #7 May 23 2023 23:10:46

%S 1,1,10,1,3,10,7,1,11,3,21,11,9,9,13,2,3,11,13,9,11,21,15,11,21,9,13,

%T 9,10,13,11,2,21,3,9,11,13,13,17,9,21,11,10,21,13,15,92,55,29,21,20,9,

%U 58,13,21,9,13,10,22,13,21,11,11,4,9,21,23,9,67,9,46,11,13,13,21,13,31,17

%N Smallest positive integer m such that n divides [8^m/m] (=A129798(m)).

%C This sequence is well-defined.

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

%F If A138255(n) is divisible by 3 then a(n)=A138255(n)/3. In general, a(n) >= A138255(n)/3.

%t spi[n_]:=Module[{m=1},While[!Divisible[Floor[8^m/m],n],m++];m]; Array[spi,80] (* _Harvey P. Dale_, Oct 23 2022 *)

%Y Cf. A129798, A138255, A138256, A138257, A138258, A138259, A138260, A138262, A138263.

%K nonn

%O 1,3

%A _Max Alekseyev_, Mar 09 2008.