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A258560 Number of (7+1) X (n+1) 0..1 arrays with every 2 X 2 subblock ne-sw antidiagonal difference nondecreasing horizontally and nw+se diagonal sum nondecreasing vertically. 1
2008, 4667, 6348, 9688, 12940, 16942, 21653, 26628, 31806, 37351, 43158, 49004, 54998, 61394, 68087, 74854, 81804, 89191, 96910, 104738, 112784, 121302, 130187, 139216, 148498, 158287, 168478, 178848, 189506, 200706, 212343, 224194, 236368 (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) - 3*a(n-2) + a(n-3) + a(n-4) - 3*a(n-5) + 3*a(n-6) - a(n-7) for n>14.

Empirical g.f.: x*(2008 - 1357*x - 1629*x^2 + 2637*x^3 - 3755*x^4 + 2195*x^5 + 1588*x^6 - 3082*x^7 + 1686*x^8 - 674*x^9 - 64*x^10 + 222*x^11 + 170*x^12 + 90*x^13) / ((1 - x)^4*(1 + x)*(1 + x^2)). - Colin Barker, Dec 22 2018

EXAMPLE

Some.solutions.for.n=4:

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

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

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

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

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

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

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

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

CROSSREFS

Row 7 of A258554.

Sequence in context: A201343 A219083 A258553 * A281987 A172735 A172780

Adjacent sequences:  A258557 A258558 A258559 * A258561 A258562 A258563

KEYWORD

nonn

AUTHOR

R. H. Hardin, Jun 03 2015

STATUS

approved

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Last modified September 25 17:14 EDT 2021. Contains 347659 sequences. (Running on oeis4.)