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A258548 Number of (n+1) X (2+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, 296, 652, 1329, 2530, 4667, 8419, 14932, 26184, 45561, 78903, 136170, 234461, 403075, 692272, 1188185, 2038466, 3496239, 5995441, 10279967, 17625041, 30216773, 51802782, 88807568, 152244537, 260993810, 447421309, 767011467 (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) = 4*a(n-1) - 5*a(n-2) + a(n-3) + 3*a(n-4) - 4*a(n-5) + 2*a(n-6) + 2*a(n-7) - 3*a(n-8) + a(n-9) for n>11.

Empirical g.f.: x*(44 - 64*x + 68*x^2 - 16*x^3 - 43*x^4 + 18*x^5 + 12*x^6 - 12*x^7 - 2*x^8 + 6*x^9 - x^10) / ((1 - x)^3*(1 - x - x^2 - x^4 + x^6)). - Colin Barker, Dec 21 2018

EXAMPLE

Some solutions for n=4:

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

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

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

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

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

CROSSREFS

Column 2 of A258554.

Sequence in context: A044231 A044612 A258555 * A036198 A094128 A340178

Adjacent sequences:  A258545 A258546 A258547 * A258549 A258550 A258551

KEYWORD

nonn

AUTHOR

R. H. Hardin, Jun 03 2015

STATUS

approved

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Last modified September 28 19:16 EDT 2021. Contains 347717 sequences. (Running on oeis4.)