A233811 Number of (n+1) X (1+1) 0..5 arrays with every 2 X 2 subblock having the sum of the squares of all six edge and diagonal differences equal to 11.

96, 428, 1824, 8136, 34848, 155488, 667200, 2977440, 12787200, 57068480, 245195520, 1094334720, 4702809600, 20989561600, 90210201600, 402629644800, 1730534860800, 7723826124800, 33198475776000, 148173756672000

Offset

1,1

Links

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

Formula

Empirical: a(n) = 30*a(n-2) - 220*a(n-4) + 240*a(n-6).

Empirical g.f.: 4*x*(24 + 107*x - 264*x^2 - 1176*x^3 + 312*x^4 + 1392*x^5) / (1 - 30*x^2 + 220*x^4 - 240*x^6). - Colin Barker, Oct 11 2018

Example

Some solutions for n=5:
..2..1....3..2....2..1....3..3....3..1....1..3....5..4....4..3....2..3....3..2
..1..3....2..4....0..2....1..2....3..2....1..2....5..3....5..5....3..1....3..1
..2..1....3..2....0..1....3..1....3..1....1..3....3..4....3..4....2..3....1..2
..1..3....1..3....0..2....1..2....2..1....3..2....2..4....2..2....1..3....3..3
..2..1....2..3....0..1....0..2....1..3....3..1....2..3....1..0....2..3....4..5
..1..3....3..1....2..0....1..2....2..3....2..3....4..4....2..0....3..1....3..5

Crossrefs

Column 1 of A233818.

Sequence in context: A179825 A304515 A233818 * A233717 A233710 A234083

Adjacent sequences: A233808 A233809 A233810 * A233812 A233813 A233814

Keyword

nonn

Author

R. H. Hardin, Dec 16 2013

Status

approved