A258552 Number of (n+1) X (6+1) 0..1 arrays with every 2 X 2 subblock ne-sw antidiagonal difference nondecreasing horizontally and nw+se diagonal sum nondecreasing vertically.

988, 683, 1917, 3314, 6662, 10854, 16942, 24300, 33844, 45166, 59274, 75580, 95044, 117306, 143422, 172852, 206604, 244366, 287242, 334740, 387916, 446506, 511662, 582940, 661444, 746958, 840682, 942220, 1052724, 1172026, 1301374, 1440420

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>14.

Empirical g.f.: x*(988 - 3269*x + 5113*x^2 - 4208*x^3 + 2176*x^4 + 374*x^5 - 2954*x^6 + 2530*x^7 - 1622*x^8 + 1571*x^9 - 743*x^10 + 82*x^11 + 6*x^12 + 4*x^13) / ((1 - x)^5*(1 + x)*(1 + x^2)). - Colin Barker, Dec 22 2018

Example

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

Crossrefs

Column 6 of A258554.

Sequence in context: A221128 A045733 A250490 * A258559 A235762 A235545

Adjacent sequences: A258549 A258550 A258551 * A258553 A258554 A258555

Keyword

nonn

Author

R. H. Hardin, Jun 03 2015

Status

approved