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A297315 Number of 2 X n 0..1 arrays with every 1 horizontally or antidiagonally adjacent to 1 or 2 neighboring 1s. 1
1, 7, 23, 66, 207, 654, 2049, 6422, 20119, 63033, 197551, 619096, 1940007, 6079365, 19051015, 59700283, 187082905, 586262278, 1837172149, 5757153010, 18041210871, 56535805498, 177166451873, 555187134041, 1739791875173, 5451991915452 (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) = 3*a(n-1) - 2*a(n-2) + 8*a(n-3) - 3*a(n-4) + 7*a(n-5) - 5*a(n-6) - a(n-7) - a(n-8) + a(n-9).

Empirical g.f.: x*(1 + x - x^2)*(1 + 3*x + 2*x^2 + 4*x^3 - x^5 - x^6) / ((1 - x + 2*x^2 - x^3)*(1 - 2*x - 2*x^2 - 5*x^3 + x^5 + x^6)). - Colin Barker, Feb 26 2019

EXAMPLE

Some solutions for n=5:

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

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

CROSSREFS

Row 2 of A297314.

Sequence in context: A066187 A259214 A114246 * A048457 A048458 A134350

Adjacent sequences:  A297312 A297313 A297314 * A297316 A297317 A297318

KEYWORD

nonn

AUTHOR

R. H. Hardin, Dec 28 2017

STATUS

approved

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Last modified June 4 01:05 EDT 2020. Contains 334808 sequences. (Running on oeis4.)