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 A273725 #12 Feb 24 2025 16:48:55 %S A273725 1,1,24,3892643213082624 %N A273725 Number of quaternary heaps on n levels (i.e., of (4^n-1)/3 elements). %C A273725 a(n) is also the number of labeled histories for a fully symmetric quadfurcating labeled topology with 4^n leaves. - _Noah A Rosenberg_, Feb 24 2025 %H A273725 Alois P. Heinz, <a href="/A273725/b273725.txt">Table of n, a(n) for n = 0..5</a> %H A273725 E. H. Dickey, N. A. Rosenberg, <a href="https://doi.org/10.1098/rstb.2023.0307">Labelled histories with multifurcation and simultaneity</a>, Phil. Trans. R. Soc. B 380 (2025), 20230307. %H A273725 Wikipedia, <a href="https://en.wikipedia.org/wiki/D-ary_heap">D-ary heap</a> %F A273725 a(n) = A178009(A002450(n)). %Y A273725 Column k=4 of A273712. %Y A273725 Cf. A002450, A178009. %K A273725 nonn %O A273725 0,3 %A A273725 _Alois P. Heinz_, May 28 2016