This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A127998 #28 Apr 13 2018 06:21:26 %S A127998 3,5,19,53,71,653,661,10343,49307,115597,152783 %N A127998 Numbers n such that (24^n - 1)/23 is prime. %C A127998 Note that 10343 was known to be a term of this sequence before 653 and 661. - _Alonso del Arte_, Mar 17 2014 %H A127998 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 A127998 Henri Lifchitz, <a href="http://www.primenumbers.net/Henri/us/MersFermus.htm">Mersenne and Fermat primes field</a> %H A127998 <a href="/index/Pri#primepop">Index to primes in various ranges</a>, form ((k+1)^n-1)/k %t A127998 Select[Prime[Range[100]], PrimeQ[(24^# - 1)/23] &] %o A127998 (PARI) isok(n) = isprime((24^n-1)/23); \\ _Michel Marcus_, Mar 13 2016 %K A127998 hard,more,nonn %O A127998 1,1 %A A127998 _Alexander Adamchuk_, Feb 11 2007 %E A127998 a(6) and a(7) from Herman Jamke (hermanjamke(AT)fastmail.fm), Jan 05 2008 %E A127998 a(8) from _Richard Fischer_ in 2004. %E A127998 a(9) from _Robert Price_, Apr 18 2012 %E A127998 a(10) from _Paul Bourdelais_, Sep 12 2017 %E A127998 a(11) from _Paul Bourdelais_, Apr 09 2018