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 A237052 #15 Feb 16 2025 08:33:21
%S A237052 7,19,37,83,1481,12527,20149
%N A237052 Numbers n such that (49^n + 1)/50 is prime.
%C A237052 All terms are primes.
%C A237052 a(8) > 10^5.
%H A237052 J. Brillhart et al., <a href="http://dx.doi.org/10.1090/conm/022">Factorizations of b^n +- 1</a>, Contemporary Mathematics, Vol. 22, Amer. Math. Soc., Providence, RI, 3rd edition, 2002.
%H A237052 H. Dubner and T. Granlund, <a href="http://www.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 A237052 H. Lifchitz, <a href="http://www.primenumbers.net/Henri/us/MersFermus.htm">Mersenne and Fermat primes field</a>
%H A237052 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/Repunit.html">Repunit</a>.
%t A237052 Do[ p=Prime[n]; If[ PrimeQ[ (49^p + 1)/50 ], Print[p] ], {n, 1, 9592} ]
%o A237052 (PARI) is(n)=ispseudoprime((49^n+1)/50) \\ _Charles R Greathouse IV_, Jun 13 2017
%Y A237052 Cf. A000978 = numbers n such that (2^n + 1)/3 is prime.
%Y A237052 Cf. A007658, A057171, A057172, A057173, A057175, A001562, A057177, A057178, A057179, A057180, A057181, A057182, A057183, A057184, A057185, A057186, A057187, A057188, A057189, A057190, A057191, A071380, A071381, A071382, A084741, A084742, A065507, A126659, A126856, A185240, A229145, A229524, A230036, A229663, A231604, A231865, A235683, A236167, A236530.
%K A237052 hard,more,nonn
%O A237052 1,1
%A A237052 _Robert Price_, Feb 02 2014
%E A237052 Typo in description corrected by _Ray Chandler_, Feb 20 2017