A251106 Number of (n+1) X (1+1) 0..2 arrays with no 2 X 2 subblock having the maximum of its diagonal elements greater than the absolute difference of its antidiagonal elements.

37, 147, 526, 1844, 6544, 23334, 83126, 295938, 1053609, 3751373, 13356805, 47556710, 169324797, 602878211, 2146538499, 7642716637, 27211772110, 96887085837, 344964943222, 1228242247433, 4373137177399, 15570486043677

Offset

1,1

Links

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

Formula

Empirical: a(n) = 5*a(n-1) - 8*a(n-2) + 13*a(n-3) - 12*a(n-4) + 9*a(n-5) - 5*a(n-6) + a(n-7).

Empirical g.f.: x*(37 - 38*x + 87*x^2 - 91*x^3 + 65*x^4 - 41*x^5 + 10*x^6) / ((1 + x^2)*(1 - 5*x + 7*x^2 - 8*x^3 + 5*x^4 - x^5)). - Colin Barker, Nov 25 2018

Example

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

Crossrefs

Column 1 of A251113.

Sequence in context: A031690 A157324 A251113 * A141968 A142656 A145898

Adjacent sequences: A251103 A251104 A251105 * A251107 A251108 A251109

Keyword

nonn

Author

R. H. Hardin, Nov 30 2014

Status

approved