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%I #28 Apr 13 2018 06:21:26
%S 3,5,19,53,71,653,661,10343,49307,115597,152783
%N Numbers n such that (24^n - 1)/23 is prime.
%C Note that 10343 was known to be a term of this sequence before 653 and 661. - _Alonso del Arte_, Mar 17 2014
%H H. Dubner, <a href="http://dx.doi.org/10.1090/S0025-5718-1993-1185243-9">Generalized repunit primes</a>, Math. Comp., 61 (1993), 927-930.
%H Henri Lifchitz, <a href="http://www.primenumbers.net/Henri/us/MersFermus.htm">Mersenne and Fermat primes field</a>
%H <a href="/index/Pri#primepop">Index to primes in various ranges</a>, form ((k+1)^n-1)/k
%t Select[Prime[Range[100]], PrimeQ[(24^# - 1)/23] &]
%o (PARI) isok(n) = isprime((24^n-1)/23); \\ _Michel Marcus_, Mar 13 2016
%K hard,more,nonn
%O 1,1
%A _Alexander Adamchuk_, Feb 11 2007
%E a(6) and a(7) from Herman Jamke (hermanjamke(AT)fastmail.fm), Jan 05 2008
%E a(8) from _Richard Fischer_ in 2004.
%E a(9) from _Robert Price_, Apr 18 2012
%E a(10) from _Paul Bourdelais_, Sep 12 2017
%E a(11) from _Paul Bourdelais_, Apr 09 2018
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