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 A334443 #6 May 05 2020 12:34:23 %S A334443 1,0,1,2,9,33,290,3692,94280,4454654 %N A334443 Number of unlabeled connected n-vertex graphs for which the lights out puzzle has a unique solution. %C A334443 The lights out puzzle on a graph has a unique solution if and only if the graph has an odd number of matchings. (See Section 6 in the paper by Eriksson, Eriksson, and Sjöstrand.) %H A334443 H. Eriksson, K. Eriksson, J. Sjöstrand, <a href="https://doi.org/10.1006/aama.2001.0739">Note on the lamp lighting problem</a>, Advances in Applied Mathematics 27 (2001), 357-366. %H A334443 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/LightsOutPuzzle.html">Lights Out Puzzle</a> %e A334443 The connected 4-vertex graphs for which the lights out puzzle has a unique solution are the path and the cycle, so a(4)=2. %Y A334443 Cf. A076436. %Y A334443 Inverse Euler transform of A334444. %K A334443 nonn,more %O A334443 1,4 %A A334443 _Pontus von Brömssen_, Apr 30 2020