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A231865
Numbers n such that (43^n + 1)/44 is prime.
4
5, 7, 19, 251, 277, 383, 503, 3019, 4517, 9967, 29573
OFFSET
1,1
COMMENTS
All terms are primes.
a(11) > 10^5.
LINKS
J. Brillhart et al., Factorizations of b^n +- 1, Contemporary Mathematics, Vol. 22, Amer. Math. Soc., Providence, RI, 3rd edition, 2002.
H. Dubner and T. Granlund, Primes of the Form (b^n+1)/(b+1), J. Integer Sequences, 3 (2000), #P00.2.7.
Eric Weisstein's World of Mathematics, Repunit.
MATHEMATICA
Do[ p=Prime[n]; If[ PrimeQ[ (43^p + 1)/44 ], Print[p] ], {n, 1, 9592} ]
PROG
(PARI) is(n)=ispseudoprime((43^n+1)/44) \\ Charles R Greathouse IV, Feb 20 2017
KEYWORD
hard,more,nonn
AUTHOR
Robert Price, Nov 14 2013
STATUS
approved