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 A347321 #3 Sep 12 2021 12:23:07 %S A347321 5,37,145,471,901,2185,3969,5563,11141,17293,21913,36479,50485,51661, %T A347321 90753,118355,139861,191445,238481 %N A347321 A146212(2*n). %C A347321 No formula is known. %Y A347321 Cf. A146212, A347319. %K A347321 nonn,more %O A347321 2,1 %A A347321 _N. J. A. Sloane_, Sep 12 2021