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A269285 Number of n X 4 0..3 arrays with some element plus some horizontally or antidiagonally adjacent neighbor totalling three no more than once. 1
216, 19188, 1363572, 87559668, 5306911092, 309846524148, 17623065834612, 983118947312628, 54032675767734132, 2934733632740325108, 157871441490222209652, 8425105813832255961588, 446611038737537558861172 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..210

FORMULA

Empirical: a(n) = 98*a(n-1) - 2401*a(n-2) for n>3.

Conjectures from Colin Barker, Jan 21 2019: (Start)

G.f.: 36*x*(1 - x)*(6 - 49*x) / (1 - 49*x)^2.

a(n) = 36 * (49^(n-2) * (240*n+53)) for n>1.

(End)

EXAMPLE

Some solutions for n=2:

..3..0..2..0. .3..1..1..3. .1..3..3..2. .3..2..0..2. .0..0..2..3

..2..0..2..3. .1..3..2..1. .3..3..3..0. .3..0..2..2. .2..2..2..0

CROSSREFS

Column 4 of A269289.

Sequence in context: A223359 A046234 A229408 * A133052 A078204 A230466

Adjacent sequences:  A269282 A269283 A269284 * A269286 A269287 A269288

KEYWORD

nonn

AUTHOR

R. H. Hardin, Feb 21 2016

STATUS

approved

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Last modified August 3 12:51 EDT 2021. Contains 346438 sequences. (Running on oeis4.)