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 A303791 #19 Apr 21 2024 22:08:57 %S A303791 5310721,2278677961,9593125081,29859667201,467593730289953281, %T A303791 98538479002618905601,146842414757227736821 %N A303791 Carmichael numbers (A002997) that are central polygonal numbers (A002061). %C A303791 Also, Carmichael numbers of the form k^2 + k + 1. %C A303791 Also, Carmichael numbers of the form k^2 - k + 1. %C A303791 There are no other terms below 10^22. %C A303791 Carmichael numbers m such that 4m - 3 is square. - _Thomas Ordowski_, Apr 30 2018 %H A303791 Claude Goutier, <a href="http://www-labs.iro.umontreal.ca/~goutier/OEIS/A055553/">Compressed text file carm10e22.gz containing all the Carmichael numbers up to 10^22</a>. %Y A303791 Intersection of A002997 and A002061. %Y A303791 Cf. A265285, A265628. %K A303791 nonn,more,hard %O A303791 1,1 %A A303791 _Max Alekseyev_, Apr 30 2018 %E A303791 a(6)-a(7) calculated using data from _Claude Goutier_ and added by _Amiram Eldar_, Apr 20 2024