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 A334248 #28 Feb 16 2025 08:34:00
%S A334248 1,1,3,54,511863,12284402192625939
%N A334248 Number of distinct acyclic orientations of the edges of an n-dimensional cube.
%C A334248 a(n) is the number of acyclic orientations of the edges of an n-dimensional cube, with rotations and reflections of the same orientation not counted.
%C A334248 Except for n=0 and n=2, a(n) can be obtained by substituting -1 for x in the chromatic polynomials given in A334358. This fails for n = 2 because the square when folded diagonally gives a graph with an odd number of vertices. The contribution from this graph needs to be negated when determining the number of acyclic orientations. - _Andrew Howroyd_, Apr 24 2020
%H A334248 Matthew Scroggs, <a href="https://github.com/mscroggs/acyclic-orientations/blob/master/a334248.py">Python code to calculate A334248</a>.
%H A334248 Mathematics Stack Exchange, <a href="https://math.stackexchange.com/questions/666987/combinatorial-problem-directed-acyclic-graph/673620#673620">Combinatorial problem: Directed Acyclic Graph</a>.
%H A334248 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/HypercubeGraph.html">Hypercube Graph</a>.
%H A334248 Wikipedia, <a href="https://en.wikipedia.org/wiki/Acyclic_orientation">Acyclic orientation</a>.
%F A334248 a(n) = Sum_{k=1..2^n} (-1)^k * A334358(n, 2^n-k)/(n!*2^n) for n >= 3. - _Andrew Howroyd_, Apr 24 2020
%Y A334248 Cf. A333418. A334247 is the number of acyclic orientations with rotations and reflections of the same orientation included.
%Y A334248 Cf. A334358.
%K A334248 nonn,more
%O A334248 0,3
%A A334248 _Matthew Scroggs_, Apr 20 2020
%E A334248 a(5) from _Andrew Howroyd_, Apr 24 2020