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A128350 Numbers k such that (14^k - 5^k)/9 is prime. 18
2, 151, 673, 709, 2999, 17909, 77213 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

All terms are primes.

a(8) > 10^5. - Robert Price, Apr 23 2013

LINKS

Table of n, a(n) for n=1..7.

MATHEMATICA

k=14; Do[p=Prime[n]; f=(k^p-5^p)/(k-5); If[ PrimeQ[f], Print[p] ], {n, 1, 200}]

PROG

(PARI) is(n)=isprime((14^n-5^n)/9) \\ Charles R Greathouse IV, Feb 17 2017

CROSSREFS

Cf. A062572, A128344, A128345, A128346, A128347, A128348, A128349, A128351, A128352, A128353, A128354. Cf. A004061, A082182, A121877, A059802. Cf. A057171, A082387, A122853, A128335, A128336, A128337, A128338, A128339, A128340, A128341, A128342.

Sequence in context: A141139 A141130 A157074 * A046473 A261967 A024245

Adjacent sequences:  A128347 A128348 A128349 * A128351 A128352 A128353

KEYWORD

hard,more,nonn

AUTHOR

Alexander Adamchuk, Feb 27 2007

EXTENSIONS

One more term from Herman Jamke (hermanjamke(AT)fastmail.fm), May 01 2008

a(6) and a(7) from Robert Price, Apr 23 2013

STATUS

approved

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Last modified June 26 20:30 EDT 2019. Contains 324380 sequences. (Running on oeis4.)