A253441 Number of (7+1) X (n+1) 0..1 arrays with every 2 X 2 subblock diagonal minus antidiagonal sum nondecreasing horizontally, vertically and ne-to-sw antidiagonally.

613, 612, 625, 660, 732, 876, 1164, 1740, 2892, 5196, 9804, 19020, 37452, 74316, 148044, 295500, 590412, 1180236, 2359884, 4719180, 9437772, 18874956, 37749324, 75498060, 150995532, 301990476, 603980364, 1207960140, 2415919692, 4831838796

Offset

1,1

Links

R. H. Hardin, Table of n, a(n) for n = 1..210

Formula

Empirical: a(n) = 3*a(n-1) - 2*a(n-2) for n>5.

Empirical: a(n) = 9*2^(n-1) + 588 for n>3.

Empirical g.f.: x*(613 - 1227*x + 15*x^2 + 9*x^3 + 2*x^4) / ((1 - x)*(1 - 2*x)). - Colin Barker, Dec 13 2018

Example

Some solutions for n=4:
..1..1..0..0..0....0..0..0..0..0....0..0..0..0..0....0..1..1..1..1
..1..1..0..0..0....1..1..1..1..1....0..0..0..0..0....1..1..1..1..1
..1..1..0..0..0....0..0..0..0..0....0..0..0..0..0....0..0..0..0..0
..1..1..0..0..0....0..0..0..0..0....1..1..1..1..1....1..1..1..1..1
..1..1..0..0..0....0..0..0..0..0....1..1..1..1..1....0..0..0..0..0
..1..1..0..0..0....0..0..0..0..0....1..1..1..1..1....0..0..0..0..0
..1..1..0..0..0....1..1..1..1..1....1..1..1..1..1....1..1..1..1..1
..1..1..0..0..1....0..0..0..0..0....0..0..0..0..0....1..1..1..1..1

Crossrefs

Row 7 of A253435.

Sequence in context: A151592 A292036 A253434 * A253158 A159641 A100364

Adjacent sequences: A253438 A253439 A253440 * A253442 A253443 A253444

Keyword

nonn

Author

R. H. Hardin, Dec 31 2014

Status

approved