A250463 Number of (n+1) X (3+1) 0..1 arrays with nondecreasing min(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.

85, 557, 3476, 21753, 135753, 847278, 5286723, 32988493, 205837420, 1284368485, 8014067309, 50005407550, 312018725543, 1946903634993, 12148095748212, 75800483328529, 472972331775681, 2951205828148958, 18414641259844987

Offset

1,1

Comments

Column 3 of A250468.

Links

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

Formula

Empirical: a(n) = 5*a(n-1) +14*a(n-2) -35*a(n-3) -37*a(n-4) +68*a(n-5) +30*a(n-6) -44*a(n-7) -8*a(n-8) +8*a(n-9).

Example

Some solutions for n=5
..0..1..0..0....0..0..1..0....0..0..0..0....0..0..0..0....1..0..0..0
..1..0..1..0....1..0..0..1....0..0..0..0....0..0..0..0....0..0..0..0
..0..0..0..1....0..1..0..0....0..0..1..0....0..0..0..1....1..0..0..1
..1..0..0..0....1..0..0..0....0..1..0..1....0..0..0..0....0..1..0..1
..0..0..0..0....0..0..0..1....0..0..0..0....0..0..0..1....0..0..0..1
..1..1..0..1....0..0..1..0....0..0..1..0....1..0..1..1....1..0..0..1

Crossrefs

Cf. A250468.

Sequence in context: A251336 A262425 A264425 * A339870 A183777 A297599

Adjacent sequences: A250460 A250461 A250462 * A250464 A250465 A250466

Keyword

nonn

Author

R. H. Hardin, Nov 23 2014

Status

approved