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A297339 Number of 2 X n 0..1 arrays with every 1 horizontally or antidiagonally adjacent to 0 or 2 neighboring 1s. 1
4, 8, 22, 53, 134, 333, 833, 2078, 5190, 12956, 32349, 80764, 201645, 503445, 1256952, 3138228, 7835210, 19562153, 48840794, 121940721, 304449181, 760117722, 1897784554, 4738195288, 11829843673, 29535549464, 73741353337, 184109904521 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

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

FORMULA

Empirical: a(n) = a(n-1) + 3*a(n-2) + 2*a(n-3) - a(n-5).

Empirical g.f.: x*(4 + 4*x + 2*x^2 - x^3 - x^4) / ((1 + x)*(1 - 2*x - x^2 - x^3 + x^4)). - Colin Barker, Feb 27 2019

EXAMPLE

Some solutions for n=5:

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

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

CROSSREFS

Row 2 of A297338.

Sequence in context: A190795 A052528 A058855 * A290138 A266922 A284778

Adjacent sequences:  A297336 A297337 A297338 * A297340 A297341 A297342

KEYWORD

nonn

AUTHOR

R. H. Hardin, Dec 28 2017

STATUS

approved

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Last modified February 19 19:06 EST 2020. Contains 332047 sequences. (Running on oeis4.)