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 A032413 #30 Dec 23 2024 10:39:16 %S A032413 2,12,18,24,54,72,114,180,214,504,558,964,1098,1420,2764,4322,5582, %T A032413 10538,14634,23970,61054,67318,88958,96744,297350,357840,376162, %U A032413 723530,916980,925012,1472718,1817862,5391378 %N A032413 Numbers k such that 127*2^k+1 is prime. %H A032413 Ray Ballinger, <a href="http://www.prothsearch.com/index.html">Proth Search Page</a> %H A032413 Ray Ballinger and Wilfrid Keller, <a href="http://www.prothsearch.com/riesel1.html">List of primes k.2^n + 1 for k < 300</a> %H A032413 Y. Gallot, <a href="http://www.utm.edu/research/primes/programs/gallot/index.html">Proth.exe: Windows Program for Finding Large Primes</a> %H A032413 Wilfrid Keller, <a href="http://www.prothsearch.com/riesel2.html">List of primes k.2^n - 1 for k < 300</a> %H A032413 <a href="/index/Pri#riesel">Index entries for sequences of n such that k*2^n-1 (or k*2^n+1) is prime</a> %t A032413 Select[Range[1000], PrimeQ[127*2^# + 1] & ] (* _Robert Price_, Dec 17 2018 *) %o A032413 (PARI) is(n)=ispseudoprime(127*2^n+1) \\ _Charles R Greathouse IV_, Jun 13 2017 %Y A032413 Cf. A032418. %K A032413 nonn,more %O A032413 1,1 %A A032413 _James R. Buddenhagen_ %E A032413 a(25)-a(32) from the Ray Ballinger and Wilfrid Keller link by _Robert Price_, Dec 17 2018 %E A032413 a(33) from _Jeppe Stig Nielsen_, Dec 23 2024