A184100 One quarter the number of n X n toroidal 0..3 arrays with each element having the sum of its vertical neighbors equal to the sum of its horizontal neighbors

1, 4, 85, 484, 3661, 28900, 137845, 1322500

Offset

1,2

Comments

One quarter the number of solutions in 0..3 of a 1-d velocity-one wave equation utt=uxx on a periodic grid

Diagonal of A184101

Links

Table of n, a(n) for n=1..8.

Example

Some solutions for 5X5
..2..0..3..3..0....1..2..1..1..3....2..1..1..2..1....3..1..2..1..3
..0..2..0..3..3....2..1..2..3..0....1..0..2..2..2....2..3..2..2..1
..3..0..2..0..3....0..2..3..1..2....0..2..1..2..2....1..3..3..2..1
..3..3..0..2..0....2..2..1..2..1....3..1..2..1..0....2..1..3..2..2
..0..3..3..0..2....3..1..1..1..2....1..3..1..0..2....2..2..0..3..3

Crossrefs

Sequence in context: A225164 A229185 A360741 * A059830 A358439 A189831

Adjacent sequences: A184097 A184098 A184099 * A184101 A184102 A184103

Keyword

nonn

Author

R. H. Hardin Jan 09 2011

Status

approved