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A278275 Number of n X 3 0..1 arrays with every element both equal and not equal to some elements at offset (-1,-1) (-1,0) (-1,1) (0,-1) (0,1) or (1,0), with upper left element zero. 1
0, 4, 25, 136, 839, 5013, 30370, 183403, 1108525, 6699034, 40484839, 244664745, 1478598250, 8935711959, 54001778309, 326352531078, 1972267883095, 11919137270093, 72031712514698, 435314024068379, 2630762103695997 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..210

FORMULA

Empirical: a(n) = 6*a(n-1) + 3*a(n-2) - 17*a(n-3) + 19*a(n-5) - 16*a(n-6) + 8*a(n-7) for n>9.

Empirical g.f.: x^2*(1 - x)*(4 + 5*x - 21*x^2 - 5*x^3 - 9*x^4 + 2*x^5 - 2*x^6) / (1 - 6*x - 3*x^2 + 17*x^3 - 19*x^5 + 16*x^6 - 8*x^7). - Colin Barker, Feb 09 2019

EXAMPLE

Some solutions for n=4:

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

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

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

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

CROSSREFS

Column 3 of A278280.

Sequence in context: A220381 A015533 A207410 * A301836 A275177 A079291

Adjacent sequences:  A278272 A278273 A278274 * A278276 A278277 A278278

KEYWORD

nonn

AUTHOR

R. H. Hardin, Nov 16 2016

STATUS

approved

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Last modified September 26 01:25 EDT 2020. Contains 337346 sequences. (Running on oeis4.)