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A067946
Numbers k that divide 5^k - 1.
21
1, 2, 4, 6, 8, 12, 16, 18, 24, 32, 36, 42, 48, 52, 54, 64, 72, 84, 96, 104, 108, 126, 128, 144, 156, 162, 168, 186, 192, 208, 216, 252, 256, 272, 288, 294, 312, 324, 336, 342, 372, 378, 384, 416, 432, 468, 486, 504, 512, 544, 558, 576, 588, 624, 648, 672, 676
OFFSET
1,2
LINKS
MATHEMATICA
Join[{1}, Select[Range[700], PowerMod[5, #, #]==1&]] (* Harvey P. Dale, Feb 25 2015 *)
PROG
(PARI) is(n)=Mod(5, n)^n==1 \\ Charles R Greathouse IV, Nov 04 2016
CROSSREFS
Cf. A024049.
Sequence in context: A055932 A140067 A364157 * A227270 A145853 A318782
KEYWORD
easy,nonn
AUTHOR
Benoit Cloitre, Mar 05 2002
STATUS
approved