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A269077 Number of 3 X n binary arrays with some element plus some horizontally, diagonally or antidiagonally adjacent neighbor totalling two not more than once. 1
8, 32, 123, 521, 1887, 7477, 27042, 102070, 368391, 1351259, 4850557, 17489481, 62373468, 222422348, 788291635, 2789267661, 9831173339, 34583332541, 121320954422, 424799241314, 1484281289599, 5177412026719, 18028809567225 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
LINKS
FORMULA
Empirical: a(n) = 4*a(n-1) + 8*a(n-2) - 34*a(n-3) - 16*a(n-4) + 60*a(n-5) - 25*a(n-6).
Empirical g.f.: x*(8 - 69*x^2 + 45*x^3 + 35*x^4 - 25*x^5) / (1 - 2*x - 6*x^2 + 5*x^3)^2. - Colin Barker, Jan 18 2019
EXAMPLE
Some solutions for n=4:
..1..0..1..0. .0..0..0..0. .1..0..0..0. .1..0..0..0. .0..0..0..1
..0..0..0..1. .0..0..1..0. .0..0..0..0. .0..1..0..1. .0..0..1..0
..1..0..0..1. .1..0..1..0. .0..0..0..0. .0..1..0..1. .1..0..1..0
CROSSREFS
Row 3 of A269075.
Sequence in context: A318944 A196097 A234272 * A183915 A357789 A363333
KEYWORD
nonn
AUTHOR
R. H. Hardin, Feb 19 2016
STATUS
approved

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Last modified February 23 18:28 EST 2024. Contains 370283 sequences. (Running on oeis4.)