A258550 Number of (n+1) X (4+1) 0..1 arrays with every 2 X 2 subblock ne-sw antidiagonal difference nondecreasing horizontally and nw+se diagonal sum nondecreasing vertically.

228, 344, 985, 1891, 3754, 6196, 9688, 14216, 20285, 27687, 36927, 48039, 61576, 77378, 95998, 117518, 142539, 170949, 203349, 239869, 281158, 327152, 378500, 435380, 498489, 567811, 644043, 727411, 818660, 917822, 1025642, 1142394

Offset

1,1

Links

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

Formula

Empirical: a(n) = 4*a(n-1) - 6*a(n-2) + 4*a(n-3) - 4*a(n-5) + 6*a(n-6) - 4*a(n-7) + a(n-8) for n>12.

Empirical g.f.: x*(228 - 568*x + 977*x^2 - 897*x^3 + 724*x^4 - 502*x^5 - 128*x^6 + 412*x^7 - 433*x^8 + 357*x^9 - 136*x^10 + 14*x^11) / ((1 - x)^5*(1 + x)*(1 + x^2)). - Colin Barker, Dec 21 2018

Example

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

Crossrefs

Column 4 of A258554.

Sequence in context: A090943 A252451 A305063 * A335269 A252228 A252221

Adjacent sequences: A258547 A258548 A258549 * A258551 A258552 A258553

Keyword

nonn

Author

R. H. Hardin, Jun 03 2015

Status

approved