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A280552 Number of n X 6 0..1 arrays with no element equal to more than one of its horizontal and vertical neighbors, with the exception of exactly two elements, and with new values introduced in order 0 sequentially upwards. 1
6, 194, 670, 1666, 3438, 6502, 11697, 20440, 35226, 60300, 102974, 175746, 299975, 512080, 874058, 1491286, 2542606, 4331134, 7369949, 12526488, 21265610, 36058400, 61069118, 103308602, 174569331, 294669456, 496887354, 837059626 (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) = 6*a(n-1) - 12*a(n-2) + 5*a(n-3) + 12*a(n-4) - 12*a(n-5) - 3*a(n-6) + 6*a(n-7) - a(n-9) for n>12.

Empirical g.f.: x*(6 + 158*x - 422*x^2 - 56*x^3 + 440*x^4 + 260*x^5 - 83*x^6 - 314*x^7 + 22*x^8 - 45*x^9 - 142*x^10 + 4*x^11) / ((1 - x)^3*(1 - x - x^2)^3). - Colin Barker, Feb 13 2019

EXAMPLE

Some solutions for n=4:

..0..1..0..1..0..1. .0..1..0..1..1..0. .0..1..1..0..0..1. .0..0..1..0..0..0

..1..0..1..0..1..0. .1..0..1..0..1..0. .0..1..0..1..0..1. .1..1..0..1..0..1

..0..1..0..1..0..1. .0..1..0..1..0..1. .1..0..1..0..1..0. .0..0..1..0..1..0

..0..0..1..1..0..1. .1..0..1..1..0..1. .1..0..1..0..1..0. .0..1..0..1..0..1

CROSSREFS

Column 6 of A280554.

Sequence in context: A156122 A281501 A283884 * A241137 A086065 A200824

Adjacent sequences:  A280549 A280550 A280551 * A280553 A280554 A280555

KEYWORD

nonn

AUTHOR

R. H. Hardin, Jan 05 2017

STATUS

approved

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Last modified September 20 05:51 EDT 2019. Contains 327212 sequences. (Running on oeis4.)