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A123061 Numbers k that divide 5^k - 3. 10
1, 2, 22, 77, 242, 371, 16102, 45727, 73447, 81286, 112277, 368237, 10191797, 13563742, 30958697, 389974222, 6171655457, 55606837682, 401469524477, 434715808966, 1729670231597, 12399384518278, 28370781933478, 32458602019394, 45360785149757, 1073804398767214 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Some larger terms: 10157607413638637338691, 678641208236297002873422185407157785099272404809011007522511134591325167. - Max Alekseyev, Oct 20 2016

LINKS

Table of n, a(n) for n=1..26.

MATHEMATICA

Select[Range[1000000], IntegerQ[(PowerMod[5, #, # ]-3)/# ]&]

Do[If[IntegerQ[(PowerMod[5, n, n ]-3)/n], Print[n]], {n, 10^9}] (* Ryan Propper, Dec 30 2006 *)

PROG

(PARI) is(n)=Mod(5, n)^n==3 \\ Charles R Greathouse IV, Nov 04 2016

CROSSREFS

Cf. A050259, A130422, A277554, A116629.

Solutions to 5^n == k (mod n): A067946 (k=1), A015951 (k=-1), A124246 (k=2), A123062 (k=-2), this sequence (k=3), A123052 (k=-3), A125949 (k=4), A123047 (k=-4), A123091 (k=5), A015891 (k=-5), A277350 (k=6), A277348 (k=-6).

Sequence in context: A156480 A226406 A226335 * A050853 A291915 A172229

Adjacent sequences:  A123058 A123059 A123060 * A123062 A123063 A123064

KEYWORD

nonn

AUTHOR

Alexander Adamchuk, Nov 04 2006

EXTENSIONS

More terms from Farideh Firoozbakht, Nov 18 2006

Corrected and extended by Ryan Propper, Jan 01 2007

Entry revised by N. J. A. Sloane, Jan 24 2007

a(18) from Lars Blomberg, Dec 12 2011

a(19)-a(26) from Max Alekseyev, Oct 20 2016

STATUS

approved

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Last modified September 21 20:10 EDT 2021. Contains 347598 sequences. (Running on oeis4.)