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A297584 Number of 3 X n 0..1 arrays with every 1 horizontally, diagonally or antidiagonally adjacent to 1 or 4 neighboring 1s. 1
1, 9, 36, 72, 188, 688, 2085, 5497, 16037, 49553, 144816, 413800, 1217824, 3611968, 10551977, 30756729, 90335433, 265402081, 776832420, 2274331728, 6670542132, 19558546400, 57298805509, 167902287673, 492193237461, 1442605306409 (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) = a(n-1) + a(n-2) + 8*a(n-3) + 18*a(n-4) + a(n-5) - 11*a(n-6) - 12*a(n-7) - a(n-8).

Empirical g.f.: x*(1 + 8*x + 26*x^2 + 19*x^3 - 10*x^4 - 23*x^5 - 13*x^6 - x^7) / (1 - x - x^2 - 8*x^3 - 18*x^4 - x^5 + 11*x^6 + 12*x^7 + x^8). - Colin Barker, Mar 01 2019

EXAMPLE

Some solutions for n=7:

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

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

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

CROSSREFS

Row 3 of A297582.

Sequence in context: A294952 A068810 A077115 * A073946 A016766 A242538

Adjacent sequences:  A297581 A297582 A297583 * A297585 A297586 A297587

KEYWORD

nonn

AUTHOR

R. H. Hardin, Jan 01 2018

STATUS

approved

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Last modified December 2 02:12 EST 2021. Contains 349435 sequences. (Running on oeis4.)