A251243 Number of (n+1) X (2+1) 0..2 arrays with no 2 X 2 subblock having the sum of its diagonal elements less than the minimum of its antidiagonal elements.

621, 14265, 327753, 7530633, 173028393, 3975606801, 91345992921, 2098821870081, 48223825786089, 1108020364732593, 25458559305394041, 584951560945849089, 13440207851070791625, 308810505245808515409, 7095420636859874120985

Offset

1,1

Links

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

Formula

Empirical: a(n) = 27*a(n-1) - 94*a(n-2) + 36*a(n-3) - 4*a(n-4) - 36*a(n-5).

Empirical g.f.: 9*x*(69 - 278*x + 108*x^2 - 16*x^3 - 108*x^4) / (1 - 27*x + 94*x^2 - 36*x^3 + 4*x^4 + 36*x^5). - Colin Barker, Nov 27 2018

Example

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

Crossrefs

Column 2 of A251249.

Sequence in context: A335767 A189119 A203086 * A184226 A260764 A224432

Adjacent sequences: A251240 A251241 A251242 * A251244 A251245 A251246

Keyword

nonn

Author

R. H. Hardin, Dec 01 2014

Status

approved