A138257 Smallest positive integer m such that n divides [4^m/m] (=A129794(m)).

1, 1, 3, 1, 7, 5, 3, 2, 7, 7, 6, 5, 7, 13, 7, 4, 5, 7, 9, 7, 3, 6, 10, 22, 11, 7, 19, 13, 15, 7, 6, 4, 31, 5, 13, 7, 19, 20, 7, 22, 11, 13, 15, 31, 7, 24, 10, 69, 43, 11, 5, 7, 44, 19, 31, 26, 9, 15, 42, 7, 31, 6, 13, 4, 7, 31, 69, 5, 67, 13, 124, 26, 9, 19, 11, 20, 31, 7, 18, 69, 28, 11, 126

Offset

1,3

Comments

This sequence is well-defined.

Links

Table of n, a(n) for n=1..83.

Romanian Master in Mathematics Contest, Problem 3, Bucharest, 2007.

Mathematica

spi[n_]:=Module[{m=1}, While[!Divisible[Floor[4^m/m], n], m++]; m]; Array[ spi, 90] (* Harvey P. Dale, Sep 13 2020 *)

Crossrefs

Cf. A129794, A138255, A138256, A138258, A138259, A138260, A138261, A138262, A138263.

Sequence in context: A098966 A021763 A261693 * A283975 A071043 A375584

Adjacent sequences: A138254 A138255 A138256 * A138258 A138259 A138260

Keyword

nonn

Author

Max Alekseyev, Mar 09 2008.

Status

approved