A232251 Number of (n+1) X (2+1) 0..2 arrays with every element both >= and <= some horizontal or antidiagonal neighbor.

37, 421, 4711, 52779, 591181, 6622029, 74175439, 830862931, 9306762101, 104248027381, 1167715590199, 13079956849787, 146512791834269, 1641136772671133, 18382899355702175, 205912751666562211

Offset

1,1

Links

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

Formula

Empirical: a(n) = 10*a(n-1) + 14*a(n-2) - 6*a(n-3) - a(n-4).

Empirical g.f.: x*(37 + 51*x - 17*x^2 - 3*x^3) / (1 - 10*x - 14*x^2 + 6*x^3 + x^4). - Colin Barker, Oct 03 2018

Example

Some solutions for n=4:
..0..0..2....0..0..0....2..2..2....0..0..0....0..0..1....2..2..0....0..0..2
..0..2..1....0..0..2....0..0..0....1..2..1....1..2..2....0..0..1....0..2..2
..2..1..1....1..2..0....0..0..0....2..1..1....2..1..0....1..2..2....2..2..1
..1..2..1....2..0..0....1..2..2....1..0..0....0..0..2....0..0..1....0..0..1
..2..0..0....0..2..2....2..2..2....0..2..2....0..2..2....1..1..1....0..2..2

Crossrefs

Column 2 of A232257.

Sequence in context: A083818 A090023 A254682 * A232259 A232046 A218376

Adjacent sequences: A232248 A232249 A232250 * A232252 A232253 A232254

Keyword

nonn

Author

R. H. Hardin, Nov 21 2013

Status

approved