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A281558 Number of nX3 0..1 arrays with no element equal to more than two of its horizontal, diagonal or antidiagonal neighbors, with the exception of exactly two elements, and with new values introduced in order 0 sequentially upwards. 1
0, 5, 68, 815, 4172, 18020, 62882, 201551, 605398, 1743548, 4863258, 13228596, 35268263, 92503663, 239307757, 611896213, 1548973531, 3887082301, 9679914966, 23942689688, 58864085078, 143936487738, 350238677040, 848456244849 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Column 3 of A281563.

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) +17*a(n-3) -45*a(n-4) +60*a(n-5) -3*a(n-6) +33*a(n-8) -255*a(n-9) +303*a(n-10) -195*a(n-11) +105*a(n-12) +96*a(n-13) -348*a(n-14) +644*a(n-15) -528*a(n-16) +48*a(n-17) +304*a(n-18) -384*a(n-19) +192*a(n-20) -64*a(n-21) for n>29

EXAMPLE

Some solutions for n=4

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

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

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

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

CROSSREFS

Cf. A281563.

Sequence in context: A003361 A336433 A099334 * A165396 A029812 A208562

Adjacent sequences:  A281555 A281556 A281557 * A281559 A281560 A281561

KEYWORD

nonn

AUTHOR

R. H. Hardin, Jan 24 2017

STATUS

approved

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Last modified November 29 09:18 EST 2020. Contains 338765 sequences. (Running on oeis4.)