A258557 Number of (4+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.

228, 652, 1244, 1891, 2509, 3314, 4313, 5356, 6331, 7470, 8820, 10231, 11591, 13132, 14901, 16748, 18561, 20572, 22828, 25179, 27513, 30062, 32873, 35796, 38719, 41874, 45308, 48871, 52451, 56280, 60405, 64676, 68981, 73552, 78436, 83483, 88581, 93962

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>11.

Empirical g.f.: x*(228 - 32*x - 28*x^2 - 113*x^3 - 312*x^4 + 248*x^5 + 35*x^6 - 37*x^7 - 28*x^8 + 16*x^9 + 40*x^10) / ((1 - x)^4*(1 + x)*(1 + x^2)). - Colin Barker, Dec 22 2018

Example

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

Crossrefs

Row 4 of A258554.

Sequence in context: A128808 A043411 A172531 * A206005 A228963 A252220

Adjacent sequences: A258554 A258555 A258556 * A258558 A258559 A258560

Keyword

nonn

Author

R. H. Hardin, Jun 03 2015

Status

approved