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 A112273 #34 Dec 23 2024 14:53:42 %S A112273 5,15,365,945 %N A112273 A puzzle sequence, answer unknown. %C A112273 Possible solution is a(1) = 5; a(n) = 5 + 5 * n * A215148(n-1), giving 5, 15, 365, 945, 1755, 2795, 4065, 5565, 7295, 9255, 11445, 13865, 16515, 19395, ... . - _Michal Paulovic_, Sep 15 2023 %H A112273 Floor en Lyanne van Lamoen, <a href="https://web.archive.org/web/*/http://list.seqfan.eu/pipermail/seqfan/2005-November/043712.html">puzzle sequences</a> from "Ask Dr. Math". Nov 28, 2005. %Y A112273 Cf. A215148. %K A112273 nonn,unkn %O A112273 1,1 %A A112273 _N. J. A. Sloane_, Nov 24 2005