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%I #17 Jan 06 2025 13:34:29
%S 7,11,19,2207,2477,4951,821497
%N Numbers k such that (24^k+1)/25 is a prime.
%C a(7) > 10^5. - _Robert Price_, Jun 04 2013
%H H. Dubner and T. Granlund, <a href="https://cs.uwaterloo.ca/journals/JIS/VOL3/DUBNER/dubner.html">Primes of the Form (b^n+1)/(b+1)</a>, J. Integer Sequences, 3 (2000), #P00.2.7.
%H H. Lifchitz, <a href="http://www.primenumbers.net/Henri/us/MersFermus.htm">Mersenne and Fermat primes field</a>
%o (PARI) isok(n) = (denominator(p=(24^n+1)/25)==1) && isprime(p); \\ _Michel Marcus_, Oct 30 2017
%K nonn,more
%O 1,1
%A _N. J. A. Sloane_, Sep 15 2000
%E a(7) from _Paul Bourdelais_, Jan 06 2025