A281339 - OEIS

A281339

Number of n X 3 0..1 arrays with no element equal to more than three of its king-move neighbors and with new values introduced in order 0 sequentially upwards.

4, 25, 68, 193, 544, 1539, 4355, 12332, 34907, 98797, 279622, 791433, 2240071, 6340292, 17945485, 50792619, 143762646, 406903731, 1151694633, 3259740340, 9226322979, 26114053785, 73912847850, 209201878257, 592122035615

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OFFSET

1,1

LINKS

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

FORMULA

Empirical: a(n) = 3*a(n-1) - a(n-2) - a(n-3) + 7*a(n-4) - a(n-5) + 2*a(n-6) + 2*a(n-7) + 2*a(n-9) for n>10.

Empirical g.f.: x*(4 + 13*x - 3*x^2 + 18*x^3 + 30*x^4 - 3*x^5 + 16*x^6 + 9*x^7 + 4*x^8 + 4*x^9) / (1 - 3*x + x^2 + x^3 - 7*x^4 + x^5 - 2*x^6 - 2*x^7 - 2*x^9). - Colin Barker, Feb 18 2019

EXAMPLE

Some solutions for n=4:

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

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

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

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

CROSSREFS

Column 3 of A281344.

Sequence in context: A376483 A302324 A303017 * A298282 A077205 A180569

Adjacent sequences: A281336 A281337 A281338 * A281340 A281341 A281342

KEYWORD

nonn

AUTHOR

R. H. Hardin, Jan 20 2017

STATUS

approved