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A232251 Number of (n+1) X (2+1) 0..2 arrays with every element both >= and <= some horizontal or antidiagonal neighbor. 2
37, 421, 4711, 52779, 591181, 6622029, 74175439, 830862931, 9306762101, 104248027381, 1167715590199, 13079956849787, 146512791834269, 1641136772671133, 18382899355702175, 205912751666562211 (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) = 10*a(n-1) + 14*a(n-2) - 6*a(n-3) - a(n-4).

Empirical g.f.: x*(37 + 51*x - 17*x^2 - 3*x^3) / (1 - 10*x - 14*x^2 + 6*x^3 + x^4). - Colin Barker, Oct 03 2018

EXAMPLE

Some solutions for n=4:

..0..0..2....0..0..0....2..2..2....0..0..0....0..0..1....2..2..0....0..0..2

..0..2..1....0..0..2....0..0..0....1..2..1....1..2..2....0..0..1....0..2..2

..2..1..1....1..2..0....0..0..0....2..1..1....2..1..0....1..2..2....2..2..1

..1..2..1....2..0..0....1..2..2....1..0..0....0..0..2....0..0..1....0..0..1

..2..0..0....0..2..2....2..2..2....0..2..2....0..2..2....1..1..1....0..2..2

CROSSREFS

Column 2 of A232257.

Sequence in context: A083818 A090023 A254682 * A232259 A232046 A218376

Adjacent sequences:  A232248 A232249 A232250 * A232252 A232253 A232254

KEYWORD

nonn

AUTHOR

R. H. Hardin, Nov 21 2013

STATUS

approved

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Last modified August 3 00:25 EDT 2021. Contains 346429 sequences. (Running on oeis4.)