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A283858 Number of 2 X n 0..1 arrays with no 1 equal to more than three of its horizontal, diagonal and antidiagonal neighbors. 1
4, 16, 61, 233, 896, 3444, 13225, 50789, 195076, 749256, 2877717, 11052673, 42450984, 163045180, 626221537, 2405182717, 9237791852, 35480380112, 136272540429, 523393640665, 2010242874320, 7720912327300, 29654370583449 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
LINKS
FORMULA
Empirical: a(n) = 3*a(n-1) + a(n-2) + 7*a(n-3) + 6*a(n-4).
Empirical g.f.: x*(4 + 4*x + 9*x^2 + 6*x^3) / (1 - 3*x - x^2 - 7*x^3 - 6*x^4). - Colin Barker, Feb 22 2019
EXAMPLE
Some solutions for n=4:
..0..0..1..0. .1..0..0..0. .0..0..0..1. .0..1..1..0. .1..1..1..0
..1..0..0..1. .1..1..1..1. .1..0..0..1. .0..1..0..1. .1..1..0..1
CROSSREFS
Row 2 of A283857.
Sequence in context: A103820 A206570 A206790 * A283409 A192468 A364921
KEYWORD
nonn
AUTHOR
R. H. Hardin, Mar 17 2017
STATUS
approved

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Last modified March 28 09:04 EDT 2024. Contains 371240 sequences. (Running on oeis4.)