A250802 Number of (5+1) X (n+1) 0..1 arrays with nondecreasing min(x(i,j),x(i,j-1)) in the i direction and nondecreasing absolute value of x(i,j)-x(i-1,j) in the j direction.

338, 1336, 4258, 12062, 31220, 76110, 177142, 398704, 874298, 1879862, 3980276, 8328038, 17263070, 35523840, 72679858, 148022462, 300378084, 607796942, 1227019286, 2472564224, 4975146938, 9998914966, 20076555908, 40280556422

Offset

1,1

Links

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

Formula

Empirical: a(n) = 5*a(n-1) - 6*a(n-2) - 7*a(n-3) + 18*a(n-4) - 3*a(n-5) - 14*a(n-6) + 7*a(n-7) + 3*a(n-8) - 2*a(n-9).

Empirical g.f.: 2*x*(169 - 177*x - 197*x^2 + 577*x^3 - 137*x^4 - 423*x^5 + 221*x^6 + 95*x^7 - 64*x^8) / ((1 - x)^4*(1 + x)^2*(1 - 2*x)*(1 - x - x^2)). - Colin Barker, Nov 20 2018

Example

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

Crossrefs

Row 5 of A250797

Sequence in context: A261707 A202443 A188213 * A186052 A186044 A070311

Adjacent sequences: A250799 A250800 A250801 * A250803 A250804 A250805

Keyword

nonn

Author

R. H. Hardin, Nov 27 2014

Status

approved