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A143665 a(n) is the least prime such that the multiplicative order of 5 mod a(n) equals n. 0
2, 3, 31, 13, 11, 7, 19531, 313, 19, 521, 12207031, 601, 305175781, 29, 181, 17, 409, 5167, 191, 41, 379, 23, 8971, 390001, 101, 5227, 109, 234750601, 59, 61, 1861, 2593, 199, 3061, 211, 37, 149, 761, 79, 241, 2238236249, 43, 1644512641, 89, 1171, 47 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..46.

MATHEMATICA

p = 2; t = Table[0, {100}]; While[p < 3000000001, a = MultiplicativeOrder[5, p]; If[0 < a < 101 && t[[a]] == 0, t[[a]] = p]; p = NextPrime@ p]; t (* Robert G. Wilson v, Oct 13 2014 *)

CROSSREFS

Cf. A064081, A143663, A112092.

Sequence in context: A093712 A035514 A114009 * A074479 A272043 A136150

Adjacent sequences:  A143662 A143663 A143664 * A143666 A143667 A143668

KEYWORD

nonn

AUTHOR

Vladimir Shevelev, Aug 28 2008

EXTENSIONS

a(23)-a(40) from Robert G. Wilson v, Oct 13 2014

a(41)-a(46) from Robert G. Wilson v, Oct 15 2014

STATUS

approved

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Last modified February 17 14:12 EST 2018. Contains 299296 sequences. (Running on oeis4.)