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A256045 Triangle read by rows: order of all-2s configuration on the n X k sandpile grid graph. 6
2, 3, 1, 7, 7, 8, 11, 5, 71, 3, 26, 9, 679, 77, 52, 41, 13, 769, 281, 17753, 29, 97, 47, 3713, 4271, 726433, 434657, 272, 153, 17, 8449, 2245, 33507, 167089, 46069729, 901, 362, 123, 81767, 8569, 24852386, 265721, 8118481057, 190818387, 73124, 571, 89, 93127, 18061, 20721019, 4213133, 4974089647, 1031151241, 1234496016491, 89893 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..55.

Laura Florescu, Daniela Morar, David Perkinson, Nicholas Salter and Tianyuan Xu, Sandpiles and Dominos, Electronic Journal of Combinatorics, Volume 22(1), 2015.

David Perkinson, Lecture 15: Sandpiles, PCMI 2008 Undergraduate Summer School.

FORMULA

From Andrey Zabolotskiy, Oct 22 2021: (Start)

It seems that T(k, 1) = A005246(k+2).

For the formula for T(k, 2), see the theorem by Morar and Perkinson in Perkinson's slides.

T(n, k) divides A348566(n, k). (End)

EXAMPLE

Triangle begins:

[2]

[3, 1]

[7, 7, 8]

[11, 5, 71, 3]

[26, 9, 679, 77, 52]

[41, 13, 769, 281, 17753, 29]

[97, 47, 3713, 4271, 726433, 434657, 272]

[153, 17, 8449, 2245, 33507, 167089, 46069729, 901]

[362, 123, 81767, 8569, 24852386, 265721, 8118481057, 190818387, 73124]

[571, 89, 93127, 18061, 20721019, 4213133, 4974089647, 1031151241, 1234496016491, 89893]

...

CROSSREFS

Main diagonal gives A256046, A256043, and A256047.

Cf. A005246, A195549, A348566.

Sequence in context: A328398 A085588 A118008 * A173459 A121637 A247370

Adjacent sequences:  A256042 A256043 A256044 * A256046 A256047 A256048

KEYWORD

nonn,tabl

AUTHOR

N. J. A. Sloane, Mar 15 2015

EXTENSIONS

Column 1 added by Andrey Zabolotskiy, Oct 22 2021

STATUS

approved

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Last modified December 7 17:17 EST 2021. Contains 349582 sequences. (Running on oeis4.)