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A268968 Number of n X 5 0..2 arrays with some element plus some horizontally or antidiagonally adjacent neighbor totalling two not more than once. 1
144, 3312, 63792, 1125360, 18852912, 305242992, 4823705520, 74858700528, 1145496747312, 17332683832944, 259866681636528, 3866483993274864, 57157824214772784, 840294622720295280, 12294351113071353264 (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) = 30*a(n-1) - 261*a(n-2) + 540*a(n-3) - 324*a(n-4).

Empirical g.f.: 144*x*(1 - 7*x + 14*x^2 - 12*x^3) / (1 - 15*x + 18*x^2)^2. - Colin Barker, Jan 17 2019

EXAMPLE

Some solutions for n=3:

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

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

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

CROSSREFS

Column 5 of A268971.

Sequence in context: A252182 A187166 A231836 * A253134 A168371 A339056

Adjacent sequences:  A268965 A268966 A268967 * A268969 A268970 A268971

KEYWORD

nonn

AUTHOR

R. H. Hardin, Feb 16 2016

STATUS

approved

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Last modified December 4 04:49 EST 2021. Contains 349469 sequences. (Running on oeis4.)