A003559 - OEIS

A003559

Least number m such that 3^m == +- 1 (mod 3n + 1).

1, 3, 2, 3, 4, 9, 5, 10, 3, 15, 8, 9, 4, 21, 11, 21, 6, 20, 14, 5, 16, 11, 12, 6, 9, 39, 4, 16, 10, 6, 23, 24, 20, 17, 26, 27, 12, 44, 29, 5, 15, 63, 12, 9, 16, 69, 35, 14, 9, 25, 30, 39, 8, 81, 41, 39, 21, 60, 44, 45, 22, 80, 36, 8, 21, 99, 50, 8, 12, 105, 53

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OFFSET

1,2

LINKS

Table of n, a(n) for n=1..71.

MATHEMATICA

Table[Module[{m=1}, While[PowerMod[3, m, 3n+1]!=1&&PowerMod[3, m, 3n+1] != 3n, m++]; m], {n, 60}] (* Harvey P. Dale, Jul 29 2018 *)

CROSSREFS

Sequence in context: A334449 A268289 A201907 * A200599 A239947 A173093

Adjacent sequences: A003556 A003557 A003558 * A003560 A003561 A003562

KEYWORD

nonn

AUTHOR

N. J. A. Sloane

STATUS

approved