A250952 Number of (n+1) X (4+1) 0..1 arrays with no 2 X 2 subblock having its maximum diagonal element less than its minimum antidiagonal element.

780, 19208, 472712, 11633448, 286298344, 7045780240, 173396103624, 4267264603784, 105017049454880, 2584461405506568, 63603393841083832, 1565274567258578128, 38521285153870175304, 948005826546231120680

Offset

1,1

Links

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

Formula

Empirical: a(n) = 27*a(n-1) - 57*a(n-2) - 46*a(n-3) + 30*a(n-4).

Empirical g.f.: 4*x*(195 - 463*x - 361*x^2 + 240*x^3) / (1 - 27*x + 57*x^2 + 46*x^3 - 30*x^4). - Colin Barker, Nov 24 2018

Example

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

Crossrefs

Column 4 of A250956.

Sequence in context: A259924 A135198 A292063 * A139400 A115467 A338877

Adjacent sequences: A250949 A250950 A250951 * A250953 A250954 A250955

Keyword

nonn

Author

R. H. Hardin, Nov 28 2014

Status

approved