A250659 Number of (5+1) X (n+1) 0..1 arrays with nondecreasing x(i,j)-x(i,j-1) in the i direction and nondecreasing min(x(i,j),x(i-1,j)) in the j direction.

159, 286, 445, 636, 859, 1114, 1401, 1720, 2071, 2454, 2869, 3316, 3795, 4306, 4849, 5424, 6031, 6670, 7341, 8044, 8779, 9546, 10345, 11176, 12039, 12934, 13861, 14820, 15811, 16834, 17889, 18976, 20095, 21246, 22429, 23644, 24891, 26170, 27481, 28824

Offset

1,1

Links

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

Formula

Empirical: a(n) = 16*n^2 + 79*n + 64.

Conjectures from Colin Barker, Nov 15 2018: (Start)

G.f.: x*(159 - 191*x + 64*x^2) / (1 - x)^3.

a(n) = 3*a(n-1) - 3*a(n-2) + a(n-3) for n>3.

(End)

Example

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

Crossrefs

Row 5 of A250656.

Sequence in context: A270304 A281665 A329535 * A280971 A090948 A242115

Adjacent sequences: A250656 A250657 A250658 * A250660 A250661 A250662

Keyword

nonn

Author

R. H. Hardin, Nov 26 2014

Status

approved