A250928 Number of (n+1) X (1+1) 0..3 arrays with no 2 X 2 subblock having a diagonal absolute difference less than its antidiagonal absolute difference.

164, 1652, 16588, 166600, 1673388, 16808096, 168826024, 1695743636, 17032602828, 171081026028, 1718393703032, 17260107602388, 173366158128632, 1741346315841920, 17490651142232804, 175681812742310068

Offset

1,1

Links

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

Formula

Empirical: a(n) = 12*a(n-1) - 23*a(n-2) + 37*a(n-3) - 33*a(n-4).

Empirical g.f.: 4*x*(41 - 79*x + 134*x^2 - 132*x^3) / (1 - 12*x + 23*x^2 - 37*x^3 + 33*x^4). - Colin Barker, Nov 23 2018

Example

Some solutions for n=4:
..3..2....1..2....2..0....0..2....1..0....0..0....3..2....0..0....3..2....3..1
..0..1....0..3....1..1....1..3....1..3....1..1....2..1....3..3....0..1....2..0
..1..1....2..3....3..3....3..3....3..2....1..3....1..2....2..0....1..1....1..0
..2..2....2..3....1..0....3..0....3..1....1..3....1..2....1..1....0..2....0..0
..2..0....3..3....1..3....2..0....1..3....2..2....2..0....2..2....3..2....2..2

Crossrefs

Column 1 of A250935.

Sequence in context: A038670 A192993 A250935 * A205314 A229377 A209892

Adjacent sequences: A250925 A250926 A250927 * A250929 A250930 A250931

Keyword

nonn

Author

R. H. Hardin, Nov 28 2014

Status

approved