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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
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
KEYWORD
nonn
AUTHOR
R. H. Hardin, Dec 28 2017
STATUS
approved

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Last modified March 28 18:04 EDT 2024. Contains 371254 sequences. (Running on oeis4.)