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A055690 Numbers n such that 7^n == -1 (mod n-1). 0
2, 3, 5, 6, 9, 26, 45, 66, 87, 345, 765, 906, 3926, 8405, 11766, 23805, 35145, 42966, 59685, 95289, 317250, 413325, 416757, 722745, 770066, 890825, 938457, 1325826, 1921986, 3315378, 3675555, 5299250, 6791445, 6899685, 9371826, 10892313 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..36.

MATHEMATICA

Do[If[PowerMod[7, n, n-1]==n-2, Print[n]], {n, 2, 2*10^7}]

CROSSREFS

Sequence in context: A079371 A131761 A272776 * A108861 A294634 A051896

Adjacent sequences:  A055687 A055688 A055689 * A055691 A055692 A055693

KEYWORD

nonn

AUTHOR

Robert G. Wilson v, Jun 09 2000

STATUS

approved

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Last modified February 21 06:40 EST 2019. Contains 320371 sequences. (Running on oeis4.)