A256043 Order of all-2s configuration on the 2n X 2n sandpile grid graph.

1, 3, 29, 901, 89893, 5758715, 22687425

Offset

1,2

Links

Table of n, a(n) for n=1..7.

Laura Florescu, Daniela Morar, David Perkinson, Nicholas Salter, Tianyuan Xu, Sandpiles and Dominos, Illustration of recurrent identity element for the sandpile grid graph [Figure 1 from Sandpiles and Dominos paper] [Le Borgne et al., 2002, show a very similar figure - see Fig. 7.]

Laura Florescu, Daniela Morar, David Perkinson, Nicholas Salter, Tianyuan Xu, Sandpiles and Dominos, 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]

Le Borgne, Yvan, and Dominique Rossin, On the identity of the sandpile group, Discrete mathematics 256.3 (2002): 775-790.

David Perkinson, Lecture 15: Sandpiles, PCMI 2008 Undergraduate Summer School. Gives a(7).

Crossrefs

Cf. A065072, A256047.

Bisection of main diagonal of A256045.

Sequence in context: A243435 A064570 A117264 * A065072 A088389 A270883

Adjacent sequences: A256040 A256041 A256042 * A256044 A256045 A256046

Keyword

nonn,more

Author

N. J. A. Sloane, Mar 14 2015

Extensions

a(7) added by Scott R. Shannon, Apr 23 2019

Status

approved