A251082 Number of (n+1) X (2+1) 0..2 arrays with no 2 X 2 subblock having the sum of its diagonal elements greater than the absolute difference of its antidiagonal elements.

83, 284, 616, 1306, 2534, 4848, 9086, 17102, 32336, 61836, 119420, 232882, 457522, 904088, 1793778, 3569126, 7114892, 14200724, 28365600, 56687594, 113322526, 226582144, 453089606, 906091326, 1812079784, 3624040028, 7247941796

Offset

1,1

Links

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

Formula

Empirical: a(n) = 6*a(n-1) - 13*a(n-2) + 10*a(n-3) + 5*a(n-4) - 14*a(n-5) + 9*a(n-6) - 2*a(n-7) for n>8.

Empirical g.f.: x*(83 - 214*x - 9*x^2 + 472*x^3 - 549*x^4 + 204*x^5 + 29*x^6 - 26*x^7) / ((1 - x)^5*(1 + x)*(1 - 2*x)). - Colin Barker, Nov 24 2018

Example

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

Crossrefs

Column 2 of A251088.

Sequence in context: A142387 A145651 A244776 * A141570 A334644 A288172

Adjacent sequences: A251079 A251080 A251081 * A251083 A251084 A251085

Keyword

nonn

Author

R. H. Hardin, Nov 29 2014

Status

approved