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 A338458 #22 Feb 16 2025 08:34:00 %S A338458 1,2,3,4,5,6,7,1,2,3,4,5,6,7,8,2,3,4,5,6,7,8,9,3,4,1,2,3,4,5,6,4,5,2, %T A338458 3,4,5,6,7,5,6,3,4,5,6,7,8,6,7,4,5,2,3,4,5,6,7,5,6,1,2,3,4,5,6,6,7,2, %U A338458 3,4,5,6,7,7,8,3,4,3,4,5,6,7,8,4,5,2,3,4,5,6,7,5,6,3,4,5,6,7,8,6,7 %N A338458 Least number of heptagonal pyramidal numbers needed to represent n. %H A338458 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/HeptagonalPyramidalNumber.html">Heptagonal Pyramidal Number</a> %H A338458 <a href="/index/Ps#pyramidal_numbers">Index to sequences related to pyramidal numbers</a> %Y A338458 Cf. A002413, A104246, A338480, A338492, A338493, A338494, A338495, A338496. %K A338458 nonn %O A338458 1,2 %A A338458 _Ilya Gutkovskiy_, Oct 31 2020