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 A256043 #38 Jan 04 2025 07:33:38 %S A256043 1,3,29,901,89893,5758715,22687425 %N A256043 Order of all-2s configuration on the 2n X 2n sandpile grid graph. %H A256043 Laura Florescu, Daniela Morar, David Perkinson, Nicholas Salter, Tianyuan Xu, Sandpiles and Dominos, <a href="/A256043/a256043.pdf">Illustration of recurrent identity element for the sandpile grid graph</a> [Figure 1 from Sandpiles and Dominos paper] [Le Borgne et al., 2002, show a very similar figure - see Fig. 7.] %H A256043 Laura Florescu, Daniela Morar, David Perkinson, Nicholas Salter, and Tianyuan Xu, <a href="https://doi.org/10.37236/4472">Sandpiles and Dominos</a>, Electronic Journal of Combinatorics, Volume 22(1), 2015. Also arXiv:1406.0100, May 31 2014. [Mentions this sequence together with a different sequence (A065072) with the same initial terms] %H A256043 Le Borgne, Yvan, and Dominique Rossin, <a href="https://doi.org/10.1016/S0012-365X(02)00347-3">On the identity of the sandpile group</a>, Discrete mathematics 256.3 (2002): 775-790. %H A256043 David Perkinson, <a href="http://people.reed.edu/~davidp/pcmi/lectures/15combined.pdf">Lecture 15: Sandpiles</a>, PCMI 2008 Undergraduate Summer School. Gives a(7). %Y A256043 Cf. A065072, A256047. %Y A256043 Bisection of main diagonal of A256045. %K A256043 nonn,more %O A256043 1,2 %A A256043 _N. J. A. Sloane_, Mar 14 2015 %E A256043 a(7) added by _Scott R. Shannon_, Apr 23 2019