A233877 Number of (n+1) X (2+1) 0..2 arrays with every 2 X 2 subblock having the sum of the squares of all six edge and diagonal differences equal to 11.

76, 300, 1224, 5156, 22020, 95464, 415092, 1819604, 7964808, 35055940, 153816132, 677977352, 2977325268, 13129922932, 57677272968, 254401366820, 1117656904164, 4930047668872, 21659909682612, 95545254192788, 419778763578888

Offset

1,1

Links

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

Formula

Empirical: a(n) = 3*a(n-1) + 19*a(n-2) - 60*a(n-3) + 8*a(n-4) + 36*a(n-5) - 12*a(n-6).

Empirical g.f.: 4*x*(19 + 18*x - 280*x^2 + 86*x^3 + 172*x^4 - 64*x^5) / ((1 - 3*x + x^2)*(1 - 20*x^2 + 12*x^4)). - Colin Barker, Oct 12 2018

Example

Some solutions for n=5:
..0..2..2....0..0..2....0..2..0....2..2..2....2..0..2....2..0..2....0..1..0
..1..0..1....1..2..1....0..1..2....0..1..0....1..2..1....0..1..2....2..0..2
..2..2..0....2..0..2....0..2..0....0..2..0....0..2..0....2..2..0....1..0..1
..1..0..1....2..1..2....2..1..2....0..1..0....1..0..1....0..1..0....2..2..2
..2..0..2....2..0..2....0..2..0....0..2..2....2..2..0....0..2..0....0..1..0
..1..2..1....0..1..0....0..1..0....2..1..0....1..0..1....1..2..1....2..2..2

Crossrefs

Column 2 of A233883.

Sequence in context: A153676 A060316 A005571 * A067987 A167586 A234184

Adjacent sequences: A233874 A233875 A233876 * A233878 A233879 A233880

Keyword

nonn

Author

R. H. Hardin, Dec 17 2013

Status

approved