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A237052
Numbers n such that (49^n + 1)/50 is prime.
3
7, 19, 37, 83, 1481, 12527, 20149
OFFSET
1,1
COMMENTS
All terms are primes.
a(8) > 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[ (49^p + 1)/50 ], Print[p] ], {n, 1, 9592} ]
PROG
(PARI) is(n)=ispseudoprime((49^n+1)/50) \\ Charles R Greathouse IV, Jun 13 2017
KEYWORD
hard,more,nonn
AUTHOR
Robert Price, Feb 02 2014
EXTENSIONS
Typo in description corrected by Ray Chandler, Feb 20 2017
STATUS
approved