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A251151 Number of (n+1) X (1+1) 0..2 arrays with no 2 X 2 subblock having the minimum of its diagonal elements greater than the absolute difference of its antidiagonal elements. 1
65, 470, 3374, 24233, 173990, 1249276, 8969854, 64404093, 462424885, 3320236303, 23839479611, 171168778796, 1229001271939, 8824296918154, 63358938568631, 454920673442317, 3266355526135404, 23452612831159266, 168391053639773507 (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) = 7*a(n-1) + 4*a(n-2) - 20*a(n-3) + 3*a(n-4) + 8*a(n-5) - 4*a(n-6).

Empirical g.f.: x*(65 + 15*x - 176*x^2 + 35*x^3 + 68*x^4 - 36*x^5) / (1 - 7*x - 4*x^2 + 20*x^3 - 3*x^4 - 8*x^5 + 4*x^6). - Colin Barker, Nov 26 2018

EXAMPLE

Some solutions for n=4:

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

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

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

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

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

CROSSREFS

Column 1 of A251158.

Sequence in context: A219424 A020292 A251158 * A222588 A286612 A276963

Adjacent sequences:  A251148 A251149 A251150 * A251152 A251153 A251154

KEYWORD

nonn

AUTHOR

R. H. Hardin, Nov 30 2014

STATUS

approved

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Last modified May 30 14:53 EDT 2020. Contains 334726 sequences. (Running on oeis4.)