A250920 Number of (n+1) X (1+1) 0..2 arrays with no 2 X 2 subblock having its minimum diagonal element less than its minimum antidiagonal element.

58, 344, 2007, 11693, 68160, 397432, 2317569, 13514765, 78810538, 459578476, 2680000719, 15628241161, 91135020168, 531447642196, 3099100611969, 18072193466385, 105386761387818, 614555698316144, 3583739564227927

Offset

1,1

Links

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

Formula

Empirical: a(n) = 9*a(n-1) - 23*a(n-2) + 29*a(n-3) - 16*a(n-4) + 4*a(n-5).

Empirical g.f.: x*(58 - 178*x + 245*x^2 - 140*x^3 + 36*x^4) / (1 - 9*x + 23*x^2 - 29*x^3 + 16*x^4 - 4*x^5). - Colin Barker, Nov 23 2018

Example

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

Crossrefs

Column 1 of A250927.

Sequence in context: A027987 A141779 A250927 * A235673 A235730 A235443

Adjacent sequences: A250917 A250918 A250919 * A250921 A250922 A250923

Keyword

nonn

Author

R. H. Hardin, Nov 28 2014

Status

approved