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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 0
1, 4, 85, 484, 3661, 28900, 137845, 1322500 (list; graph; refs; listen; history; text; internal format)
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: A287248 A225164 A229185 * A059830 A189831 A223955

Adjacent sequences:  A184097 A184098 A184099 * A184101 A184102 A184103

KEYWORD

nonn

AUTHOR

R. H. Hardin Jan 09 2011

STATUS

approved

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Last modified December 7 19:20 EST 2021. Contains 349585 sequences. (Running on oeis4.)