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A128343
Numbers k such that (14^k + 5^k)/19 is prime.
11
3, 7, 17, 79, 17477, 19319, 49549
OFFSET
1,1
COMMENTS
All terms are primes.
a(8) > 10^5. - Robert Price, May 20 2013
MATHEMATICA
k=14; Do[p=Prime[n]; f=(k^p+5^p)/(k+5); If[ PrimeQ[f], Print[p] ], {n, 1, 100}]
PROG
(PARI) is(n)=isprime((14^n+5^n)/19) \\ Charles R Greathouse IV, Feb 17 2017
KEYWORD
hard,more,nonn
AUTHOR
Alexander Adamchuk, Feb 27 2007
EXTENSIONS
a(5)-a(7) from Robert Price, May 20 2013
STATUS
approved