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A237853 Number of (n+1) X (2+1) 0..1 arrays with no element greater than all horizontal neighbors or less than all vertical neighbors. 1
4, 14, 41, 114, 325, 943, 2731, 7876, 22702, 65489, 188972, 545229, 1572979, 4538047, 13092532, 37772848, 108976855, 314404070, 907073003, 2616956517, 7550066383, 21782363122, 62843332744, 181306523557, 523079446954, 1509113417351 (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) = 3*a(n-1) - 2*a(n-2) + 4*a(n-3) + 2*a(n-4) + a(n-5).

Empirical g.f.: x*(4 + 2*x + 7*x^2 + 3*x^3 + x^4) / (1 - 3*x + 2*x^2 - 4*x^3 - 2*x^4 - x^5). - Colin Barker, Oct 24 2018

EXAMPLE

Some solutions for n=5:

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

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

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

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

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

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

CROSSREFS

Column 2 of A237859.

Sequence in context: A326008 A196713 A261547 * A132357 A262875 A219867

Adjacent sequences:  A237850 A237851 A237852 * A237854 A237855 A237856

KEYWORD

nonn

AUTHOR

R. H. Hardin, Feb 14 2014

STATUS

approved

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Last modified December 15 09:05 EST 2019. Contains 329995 sequences. (Running on oeis4.)