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A258556 Number of (3+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
104, 296, 598, 985, 1403, 1917, 2542, 3222, 3940, 4767, 5718, 6737, 7807, 8999, 10328, 11738, 13212, 14821, 16580, 18433, 20363, 22441, 24682, 27030, 29468, 32067, 34842, 37737, 40735, 43907, 47268, 50762, 54372, 58169, 62168, 66313, 70587, 75061, 79750 (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*(104 - 16*x + 22*x^2 - 25*x^3 - 158*x^4 + 81*x^5 - 7*x^6 - 31*x^7 + 37*x^8 + 6*x^9) / ((1 - x)^4*(1 + x)*(1 + x^2)). - Colin Barker, Dec 22 2018

EXAMPLE

Some solutions for n=4:

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

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

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

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

CROSSREFS

Row 3 of A258554.

Sequence in context: A271745 A046298 A298325 * A299218 A300032 A185763

Adjacent sequences:  A258553 A258554 A258555 * A258557 A258558 A258559

KEYWORD

nonn

AUTHOR

R. H. Hardin, Jun 03 2015

STATUS

approved

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Last modified September 24 21:05 EDT 2021. Contains 347651 sequences. (Running on oeis4.)