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.

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

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