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A279263
Number of n X 3 0..1 arrays with no element equal to a strict majority of its horizontal and vertical neighbors, with the exception of exactly one element, and with new values introduced in order 0 sequentially upwards.
1
2, 10, 29, 86, 240, 626, 1603, 4030, 9973, 24388, 59068, 141920, 338689, 803630, 1897359, 4460226, 10444904, 24376990, 56720671, 131619998, 304674313, 703690416, 1621976820, 3731637260, 8570604669, 19653441614, 45002040707
OFFSET
1,1
LINKS
FORMULA
Empirical: a(n) = 4*a(n-1) - 4*a(n-2) + 2*a(n-3) - 4*a(n-4) - a(n-6) for n>9.
Empirical g.f.: x*(2 + 2*x - 3*x^2 + 6*x^3 - 8*x^5 + 5*x^6 - 4*x^7 + 2*x^8) / (1 - 2*x - x^3)^2. - Colin Barker, Feb 10 2019
EXAMPLE
Some solutions for n=4:
..0..1..0. .0..1..0. .0..1..1. .0..0..1. .0..1..1. .0..1..0. .0..0..1
..0..0..1. .1..0..1. .0..0..0. .0..1..0. .1..1..0. .1..0..0. .1..1..0
..1..1..0. .0..1..1. .0..1..1. .1..0..1. .0..0..1. .0..0..1. .0..0..0
..0..1..0. .1..0..0. .1..0..0. .0..1..0. .1..1..0. .1..1..0. .1..1..0
CROSSREFS
Column 3 of A279268.
Sequence in context: A192976 A264677 A101561 * A295525 A302274 A047112
KEYWORD
nonn
AUTHOR
R. H. Hardin, Dec 08 2016
STATUS
approved