A233785 Number of (n+1) X (1+1) 0..3 arrays with every 2 X 2 subblock having the sum of the squares of all six edge and diagonal differences equal to 11.

48, 188, 720, 2856, 11040, 43888, 169920, 675744, 2616960, 10407872, 40308480, 160311936, 620874240, 2469299968, 9563397120, 38034921984, 147306178560, 585856596992, 2268975329280, 9024021866496, 34949308784640, 138998129717248

Offset

1,1

Links

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

Formula

Empirical: a(n) = 18*a(n-2) - 40*a(n-4).

Empirical g.f.: 4*x*(12 + 47*x - 36*x^2 - 132*x^3) / (1 - 18*x^2 + 40*x^4). - Colin Barker, Oct 11 2018

Example

Some solutions for n=5:
..2..1....1..2....3..1....2..1....1..2....1..3....0..2....3..2....0..0....2..0
..0..2....2..0....3..2....2..0....0..0....2..1....1..2....1..1....2..1....2..1
..2..1....1..2....3..1....2..1....2..1....1..3....1..3....3..2....3..1....0..0
..1..3....2..0....2..1....3..3....3..1....2..3....2..1....1..3....1..2....2..1
..1..2....1..0....2..0....2..1....2..1....3..1....1..3....1..2....2..0....2..0
..0..2....2..0....1..2....2..0....3..1....2..1....3..2....2..0....1..2....1..2

Crossrefs

Column 1 of A233792.

Sequence in context: A130566 A233792 A233967 * A233960 A210250 A259038

Adjacent sequences: A233782 A233783 A233784 * A233786 A233787 A233788

Keyword

nonn

Author

R. H. Hardin, Dec 15 2013

Status

approved