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A258555 Number of (2+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
44, 112, 210, 344, 506, 683, 894, 1140, 1421, 1725, 2071, 2460, 2892, 3355, 3868, 4432, 5047, 5701, 6413, 7184, 8014, 8891, 9834, 10844, 11921, 13053, 14259, 15540, 16896, 18315, 19816, 21400, 23067, 24805, 26633, 28552, 30562, 32651, 34838, 37124, 39509 (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>10.

Empirical g.f.: x*(44 - 20*x + 6*x^2 + 6*x^3 - 52*x^4 + 7*x^5 + 13*x^6 - 5*x^7 + 8*x^8 + x^9) / ((1 - x)^4*(1 + x)*(1 + x^2)). - Colin Barker, Dec 22 2018

EXAMPLE

Some solutions for n=4:

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

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

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

CROSSREFS

Row 2 of A258554.

Sequence in context: A118483 A044231 A044612 * A258548 A036198 A094128

Adjacent sequences:  A258552 A258553 A258554 * A258556 A258557 A258558

KEYWORD

nonn

AUTHOR

R. H. Hardin, Jun 03 2015

STATUS

approved

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Last modified September 22 22:38 EDT 2021. Contains 347609 sequences. (Running on oeis4.)