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A228225
Numbers n such that (17^n + 3^n)/20 is prime.
1
37, 641, 2521, 7993, 41213
OFFSET
1,1
COMMENTS
All terms are primes.
a(6) > 10^5.
MATHEMATICA
k=17; Do[ p=Prime[n]; f=(3^p+k^p)/(k+3); If[ PrimeQ[f], Print[p]], {n, 1, 9592} ]
PROG
(PARI) is(n)=ispseudoprime((17^n+3^n)/20) \\ Charles R Greathouse IV, Jun 13 2017
CROSSREFS
KEYWORD
hard,more,nonn
AUTHOR
Robert Price, Aug 16 2013
STATUS
approved