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 A307491 #10 Feb 16 2025 08:33:55 %S A307491 1,4,10,4960,428536 %N A307491 Numbers that are both centered triangular and tetrahedral. %C A307491 If it exists, a(6) > 10^29. - _Bert Dobbelaere_, Apr 12 2019 %H A307491 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/CenteredTriangularNumber.html">Centered Triangular Number</a> %H A307491 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/TetrahedralNumber.html">Tetrahedral Number</a> %Y A307491 Intersection of A000292 and A005448. %Y A307491 Cf. A003556, A027568, A128862, A131750, A307492. %K A307491 nonn,more %O A307491 1,2 %A A307491 _Ilya Gutkovskiy_, Apr 10 2019