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A187819
Numbers k such that (9^k + 8^k)/17 is prime.
15
3, 7, 13, 19, 307, 619, 2089, 7297, 75571, 76103, 98897
OFFSET
1,1
COMMENTS
All terms are prime.
a(12) > 10^5.
MATHEMATICA
Select[ Prime[ Range[1, 100000] ], PrimeQ[ (9^# + 8^#)/17 ]& ]
PROG
(PARI) is(n)=isprime((9^n+8^n)/17) \\ Charles R Greathouse IV, Feb 17 2017
CROSSREFS
KEYWORD
nonn,hard,more
AUTHOR
Robert Price, Dec 26 2012
STATUS
approved