A251277 Number of (n+1) X (2+1) 0..3 arrays with no 2 X 2 subblock having its maximum diagonal element less than its minimum antidiagonal element.

3264, 164800, 8320896, 420152704, 21215177472, 1071238805248, 54091113672192, 2731275752121856, 137912990258285568, 6963776128082148352, 351628790523862185984, 17755138024422940530688, 896527630165476145606656

Offset

1,1

Links

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

Formula

Empirical: a(n) = 54*a(n-1) - 182*a(n-2) + 228*a(n-3) + 1152*a(n-4).

Empirical g.f.: 64*x*(51 - 179*x + 246*x^2 + 1152*x^3) / (1 - 54*x + 182*x^2 - 228*x^3 - 1152*x^4). - Colin Barker, Nov 27 2018

Example

Some solutions for n=2:
..0..0..2....3..0..0....1..3..2....1..2..0....1..3..0....1..1..3....1..3..0
..1..2..3....3..1..1....0..2..2....2..3..2....0..0..1....0..1..1....0..0..2
..0..0..3....3..0..3....0..1..3....3..3..2....2..1..2....2..1..0....2..3..3

Crossrefs

Column 2 of A251283.

Sequence in context: A253857 A358870 A337792 * A328148 A286008 A220594

Adjacent sequences: A251274 A251275 A251276 * A251278 A251279 A251280

Keyword

nonn

Author

R. H. Hardin, Dec 01 2014

Status

approved