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A279972 Number of n X 3 0..1 arrays with no element equal to a strict majority of its horizontal and antidiagonal neighbors, with the exception of exactly two elements, and with new values introduced in order 0 sequentially upwards. 1
0, 9, 50, 296, 1650, 8666, 43543, 211650, 1002602, 4652327, 21225237, 95473540, 424318824, 1866436977, 8136431834, 35191126234, 151149336828, 645183934470, 2738696392197, 11567109056460, 48632928912442, 203627897130121 (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) = 15*a(n-1) - 90*a(n-2) + 281*a(n-3) - 510*a(n-4) + 585*a(n-5) - 437*a(n-6) + 210*a(n-7) - 60*a(n-8) + 8*a(n-9) for n>10.

Empirical g.f.: x^2*(9 - 85*x + 356*x^2 - 819*x^3 + 1096*x^4 - 888*x^5 + 438*x^6 - 124*x^7 + 16*x^8) / (1 - 5*x + 5*x^2 - 2*x^3)^3. - Colin Barker, Feb 12 2019

EXAMPLE

Some solutions for n=4:

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

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

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

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

CROSSREFS

Column 3 of A279977.

Sequence in context: A257589 A231413 A007681 * A115366 A188210 A308646

Adjacent sequences:  A279969 A279970 A279971 * A279973 A279974 A279975

KEYWORD

nonn

AUTHOR

R. H. Hardin, Dec 24 2016

STATUS

approved

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Last modified October 13 19:52 EDT 2019. Contains 327981 sequences. (Running on oeis4.)