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A173718
Numbers n such that (9^n - 2^n)/7 is prime.
2
2, 3, 5, 13, 29, 37, 1021, 1399, 2137, 4493, 5521, 108553, 200807
OFFSET
1,1
COMMENTS
All terms are prime.
a(14) > 10^6.
LINKS
Jon Grantham and Andrew Granville, Fibonacci primes, primes of the form 2^n-k and beyond, arXiv:2307.07894 [math.NT], 2023.
MATHEMATICA
Select[ Prime[ Range[1, 100000] ], PrimeQ[ (9^# - 2^#)/7 ]& ]
PROG
(PARI) is(n)=ispseudoprime((9^n-2^n)/7) \\ Charles R Greathouse IV, Jun 06 2017
KEYWORD
hard,more,nonn
AUTHOR
Robert Price, Dec 22 2012
EXTENSIONS
a(12)-a(13) from Jon Grantham, Jul 29 2023
STATUS
approved