A250952 - OEIS

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

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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