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A297590 Number of n X 3 0..1 arrays with every 1 horizontally, diagonally or antidiagonally adjacent to 1 or 5 neighboring 1s. 1
1, 3, 9, 25, 69, 205, 597, 1701, 4949, 14389, 41493, 120149, 348437, 1008021, 2917653, 8451605, 24467733, 70830869, 205101333, 593841429, 1719269653, 4977934613, 14412904725, 41729378581, 120820070677, 349814724885, 1012822636821, 2932443592981, 8490378131733 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Alois P. Heinz, Table of n, a(n) for n = 0..1000 (terms n = 1..210 from R. H. Hardin)

FORMULA

Empirical: a(n) = a(n-1) + 2*a(n-2) + 10*a(n-3) + 4*a(n-4) - 8*a(n-5) - 8*a(n-6).

Empirical g.f.: 1 + x*(3 + 6*x + 10*x^2 - 4*x^3 - 16*x^4 - 8*x^5) / ((1 - x)*(1 - 2*x^2 - 12*x^3 - 16*x^4 - 8*x^5)). - Colin Barker, Mar 01 2019

EXAMPLE

Some solutions for n=7:

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

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

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

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

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

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

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

CROSSREFS

Column 3 of A297595.

Sequence in context: A211291 A211294 A211297 * A244934 A291594 A007046

Adjacent sequences:  A297587 A297588 A297589 * A297591 A297592 A297593

KEYWORD

nonn

AUTHOR

R. H. Hardin, Jan 01 2018

EXTENSIONS

a(0)=1 prepended by Alois P. Heinz, Mar 01 2019

STATUS

approved

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Last modified September 20 13:45 EDT 2020. Contains 337264 sequences. (Running on oeis4.)