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A219461 Primes p such that 2^p - 1 is a prime with primitive root 3. 0
3, 5, 7, 17, 19, 89, 107, 521 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

If A096393(n) = 3, then A000043(n) belongs to this sequence.

2^a(n) - 1 is in A001123.

The first term that is unknown is a(9), which is either 2203 or 2281.

LINKS

Table of n, a(n) for n=1..8.

Discussion titled Conjecture about multiplicative order of 3 modulo a Mersenne prime, (postings in mersenneforum.org), starting May 14 2006.

Index entries for primes by primitive root

MATHEMATICA

Select[Prime@Range[98], PrimitiveRoot[2^# - 1] == 3 &]

CROSSREFS

Subsequence of A000043.

Sequence in context: A331800 A062547 A125739 * A122853 A137258 A053341

Adjacent sequences:  A219458 A219459 A219460 * A219462 A219463 A219464

KEYWORD

hard,more,nonn

AUTHOR

Arkadiusz Wesolowski, Nov 20 2012

STATUS

approved

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Last modified August 10 22:22 EDT 2020. Contains 336403 sequences. (Running on oeis4.)