A138260 Smallest positive integer m such that n divides [7^m/m] (=A129797(m)).

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, 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, 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

Offset: 1

Author

Max Alekseyev, Mar 09 2008

Keywords

• nonn

Comments

This sequence is well-defined.

Links

• Harvey P. Dale, Table of n, a(n) for n = 1..1000
• Romanian Master in Mathematics Contest, Problem 3, Bucharest, 2007.

Crossrefs

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

Programs

Mathematica

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