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 A230484 #13 Apr 01 2024 02:38:54 %S A230484 253241,280601,580337,1207361,1678541,1909001,2419385,5173601, %T A230484 16324001,18073817,22849481,25080101,43363601,60155201,67194401, %U A230484 82870517,85519337,97924217,100943201,102004421,104857391,116090081,128987429,134696801,135969401,145348529 %N A230484 Strong pseudoprimes (base 2) that become prime when two is added. %H A230484 Amiram Eldar, <a href="/A230484/b230484.txt">Table of n, a(n) for n = 1..10000</a> (terms 1..5001 from Shyam Sunder Gupta) %e A230484 253241 is a strong pseudoprime (base 2) and 253243 is prime. %Y A230484 Cf. A001262, A230483, A230485, A230487. %K A230484 nonn %O A230484 1,1 %A A230484 _Shyam Sunder Gupta_, Oct 20 2013