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A245442 Numbers n such that (50^n - 1)/49 is prime. 2
3, 5, 127, 139, 347, 661, 2203, 6521 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

a(9) > 10^5.

All terms are prime.

LINKS

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

Harvey Dubner, Generalized repunit primes, Math. Comp., 61 (1993), 927-930.

Henri Lifchitz, Mersenne and Fermat primes field

MAPLE

A245442:=n->`if`(isprime((50^n - 1)/49), n, NULL); seq(A245442(n), n=1..100000); # Wesley Ivan Hurt, Apr 12 2014

MATHEMATICA

Select[Prime[Range[100000]], PrimeQ[(50^# - 1)/49] &]

PROG

(PARI) is(n)=ispseudoprime((50^n-1)/49) \\ Charles R Greathouse IV, Jun 13 2017

CROSSREFS

Cf. A028491, A004061, A004062, A004063, A004023, A005808, A004064, A016054, A006032, A006033, A006034, A006035, A127995, A127996, A127997, A127998, A127999, A098438, A128002, A128003, A128004, A128005, A240765, A242797, A243279, A245237.

Sequence in context: A153137 A105526 A070743 * A215239 A161749 A240589

Adjacent sequences:  A245439 A245440 A245441 * A245443 A245444 A245445

KEYWORD

hard,more,nonn

AUTHOR

Robert Price, Jul 22 2014

STATUS

approved

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Last modified December 8 08:49 EST 2019. Contains 329862 sequences. (Running on oeis4.)