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A269071 Number of n X 4 binary arrays with some element plus some horizontally, diagonally or antidiagonally adjacent neighbor totalling two not more than once. 1
13, 76, 521, 3288, 20400, 123976, 742688, 4397376, 25791040, 150081504, 867569920, 4986765312, 28523566592, 162453499008, 921756644864, 5212543265792, 29388948548608, 165253519908352, 926962234179584, 5188178346090496 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
LINKS
FORMULA
Empirical: a(n) = 12*a(n-1) - 40*a(n-2) + 8*a(n-3) + 92*a(n-4) - 32*a(n-5) - 64*a(n-6) for n>7.
Empirical g.f.: x*(13 - 80*x + 129*x^2 - 28*x^3 - 20*x^4 - 48*x^5 + 4*x^6) / (1 - 6*x + 2*x^2 + 8*x^3)^2. - Colin Barker, Jan 18 2019
EXAMPLE
Some solutions for n=4:
..1..1..0..0. .1..0..0..0. .0..0..1..0. .0..0..0..0. .0..0..0..1
..0..0..0..0. .0..0..1..0. .1..0..1..0. .0..0..1..0. .1..0..0..0
..1..0..0..0. .0..0..0..0. .0..0..0..0. .0..0..0..0. .0..1..0..0
..0..0..0..1. .0..0..1..1. .0..0..0..0. .0..0..0..0. .0..1..0..1
CROSSREFS
Column 4 of A269075.
Sequence in context: A282643 A269085 A182077 * A283539 A060717 A044200
KEYWORD
nonn
AUTHOR
R. H. Hardin, Feb 19 2016
STATUS
approved

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Last modified April 15 15:27 EDT 2024. Contains 371692 sequences. (Running on oeis4.)