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A128352 Numbers n such that (17^n - 5^n)/12 is prime. 19
5, 7, 17, 23, 43, 71, 239, 733, 1097 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

All terms are primes.

a(10) > 10^5. - Robert Price, Jun 11 2013

LINKS

Table of n, a(n) for n=1..9.

MATHEMATICA

k=17; Do[p=Prime[n]; f=(k^p-5^p)/(k-5); If[ PrimeQ[f], Print[p] ], {n, 1, 100}]

PROG

(PARI) is(n)=isprime((17^n-5^n)/12) \\ Charles R Greathouse IV, Feb 17 2017

CROSSREFS

Cf. A062572, A128344, A128345, A128346, A128347, A128348, A128349, A128350, A128351, A128353, A128354. Cf. A004061, A082182, A121877, A059802. Cf. A057171, A082387, A122853, A128335, A128336, A128337, A128338, A128339, A128340, A128341, A128342.

Sequence in context: A166109 A157755 A265812 * A025085 A175238 A240030

Adjacent sequences:  A128349 A128350 A128351 * A128353 A128354 A128355

KEYWORD

nonn,hard,more

AUTHOR

Alexander Adamchuk, Feb 27 2007

STATUS

approved

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Last modified March 22 22:17 EDT 2017. Contains 283901 sequences.