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 A334307 #75 Feb 16 2025 08:34:00
%S A334307 12,32,168,1152,9600,97920,1491840,21127680,377395200,7605964800,
%T A334307 164457216000,3935477145600,102571486617600,2858053098700800,
%U A334307 85725900868608000,2745404797943808000,93266934645620736000,3356738924418367488000,127589166595209166848000
%N A334307 Number of graceful labelings for the complete tripartite graph K_{1,1,n}.
%C A334307 Except for n = 2, a(n) = A333728(n+2) up to at least n = 6.
%H A334307 Paolo Xausa, <a href="/A334307/b334307.txt">Table of n, a(n) for n = 1..400</a> (terms 1..48 from Don Knuth)
%H A334307 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/CompleteTripartiteGraph.html">Complete Tripartite Graph</a>
%H A334307 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/GracefulLabeling.html">Graceful Labeling</a>
%F A334307 If n>1, a(n) = 4*A339891(n)*n!. - _Don Knuth_, Dec 21 2020.
%t A334307 A334307[n_]:=If[n==1,12,4n!(DivisorSum[2n+1,2^((#-1)/2)&]+DivisorSigma[0,n+1]-2^(n-1)-1)];Array[A334307, 25] (* _Paolo Xausa_, Dec 04 2023 *)
%Y A334307 Cf. A333728 (maximum number of graceful labelings for an n-node simple graph), A339891.
%K A334307 nonn
%O A334307 1,1
%A A334307 _Eric W. Weisstein_, Apr 24 2020
%E A334307 a(8) and a(9) from _Pontus von Brömssen_, Jul 25 2020
%E A334307 Terms a(10) and beyond from _Don Knuth_, Dec 21 2020