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 A057191 #15 Oct 30 2017 03:52:07 %S A057191 3,7,23,29,59,1249,1709,1823,1931,3433,8863,43201,78707 %N A057191 Numbers n such that (25^n+1)/26 is a prime. %C A057191 Some of the larger terms may only correspond to probable primes. %C A057191 a(14) > 10^5. - _Robert Price_, Jun 10 2013 %H A057191 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. %t A057191 Select[Range[0, 2000], PrimeQ[(25^# + 1) / 26] &] (* _Vincenzo Librandi_, Oct 29 2017 *) %o A057191 (PARI) isok(n) = (denominator(p=(25^n+1)/26)==1) && isprime(p); \\ _Michel Marcus_, Oct 29 2017 %K A057191 nonn,more %O A057191 1,1 %A A057191 _N. J. A. Sloane_, Sep 15 2000 %E A057191 a(12)-a(13) from _Robert Price_, Jun 10 2013