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%I #16 Jul 29 2023 22:10:45
%S 2,3,5,13,29,37,1021,1399,2137,4493,5521,108553,200807
%N Numbers n such that (9^n - 2^n)/7 is prime.
%C All terms are prime.
%C a(14) > 10^6.
%H Jon Grantham and Andrew Granville, <a href="https://arxiv.org/abs/2307.07894">Fibonacci primes, primes of the form 2^n-k and beyond</a>, arXiv:2307.07894 [math.NT], 2023.
%t Select[ Prime[ Range[1, 100000] ], PrimeQ[ (9^# - 2^#)/7 ]& ]
%o (PARI) is(n)=ispseudoprime((9^n-2^n)/7) \\ _Charles R Greathouse IV_, Jun 06 2017
%Y Cf. A004063, A028491, A057468, A059801, A121877, A128024, A128025, A128026, A128027, A128028, A128029, A128030, A128031, A128032.
%K hard,more,nonn
%O 1,1
%A _Robert Price_, Dec 22 2012
%E a(12)-a(13) from _Jon Grantham_, Jul 29 2023
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