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A117705
Numbers n such that 5^n-n^5 is prime.
10
2, 14, 26, 4646, 68484
OFFSET
1,1
LINKS
Henri & Renaud Lifchitz, PRP Records.
EXAMPLE
a(1)=2 because 2^5 - 5^2 = 7 is prime
MATHEMATICA
Do[If[PrimeQ[(5^n-n^5)], Print[n]], {n, 1, 5000}]
PROG
(PARI) is(n)=isprime(5^n-n^5) \\ Charles R Greathouse IV, Feb 17 2017
CROSSREFS
Sequence in context: A032461 A072390 A213136 * A330789 A031079 A364764
KEYWORD
hard,more,nonn
AUTHOR
Mohammed Bouayoun (Mohammed.Bouayoun(AT)sanef.com), Apr 13 2006, Jan 08 2008
EXTENSIONS
a(5) found by Donovan Johnson
First five terms confirmed by Dmitry Kamenetsky, Dec 18 2008
STATUS
approved