A184099 T(n,k) = Number of n X k toroidal 0..2 arrays with each element having the sum of its vertical neighbors equal to the sum of its horizontal neighbors.

3, 3, 3, 3, 9, 3, 3, 3, 3, 3, 3, 9, 87, 9, 3, 3, 3, 3, 3, 3, 3, 3, 9, 3, 361, 3, 9, 3, 3, 3, 87, 3, 3, 87, 3, 3, 3, 9, 3, 9, 1383, 9, 3, 9, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 9, 87, 361, 3, 7569, 3, 361, 87, 9, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 9, 3, 9, 3, 9, 20247, 9, 3, 9, 3, 9, 3, 3, 3, 87, 3

Offset

1,1

Comments

Number of solutions in 0..2 of a 1-d velocity-one wave equation utt=uxx on a periodic grid.

Links

R. H. Hardin, Table of n, a(n) for n = 1..220

Example

Table starts:
.3.3..3...3....3....3.....3......3......3.......3.3....3.3.....3....3...3.3..3
.3.9..3...9....3....9.....3......9......3.......9.3....9.3.....9....3...9.3..9
.3.3.87...3....3...87.....3......3.....87.......3.3...87.3.....3...87...3.3.87
.3.9..3.361....3....9.....3....361......3.......9.3..361.3.....9....3.361.3..9
.3.3..3...3.1383....3.....3......3......3....1383.3....3.3.....3.1383...3.3
.3.9.87...9....3.7569.....3......9.....87.......9.3.7569.3.....9...87...9
.3.3..3...3....3....3.20247......3......3.......3.3....3.3.20247....3
.3.9..3.361....3....9.....3.126025......3.......9.3..361.3.....9
.3.3.87...3....3...87.....3......3.299463.......3.3...87.3
.3.9..3...9.1383....9.....3......9......3.1912689.3....9
Some solutions for 9 X 3:
..0..2..2....0..2..2....2..2..2....1..1..1....1..2..1....0..0..2....1..2..0
..2..2..0....2..1..1....2..2..2....0..1..2....1..2..1....0..2..0....2..0..1
..2..0..2....2..1..1....2..2..2....2..1..0....2..0..2....2..0..0....0..1..2
..0..2..2....0..2..2....2..2..2....1..1..1....1..2..1....0..0..2....1..2..0
..2..2..0....2..1..1....2..2..2....0..1..2....1..2..1....0..2..0....2..0..1
..2..0..2....2..1..1....2..2..2....2..1..0....2..0..2....2..0..0....0..1..2
..0..2..2....0..2..2....2..2..2....1..1..1....1..2..1....0..0..2....1..2..0
..2..2..0....2..1..1....2..2..2....0..1..2....1..2..1....0..2..0....2..0..1
..2..0..2....2..1..1....2..2..2....2..1..0....2..0..2....2..0..0....0..1..2

Crossrefs

Sequence in context: A245441 A333793 A007428 * A074816 A203564 A369716

Adjacent sequences: A184096 A184097 A184098 * A184100 A184101 A184102

Keyword

nonn,tabl

Author

R. H. Hardin, Jan 09 2011

Status

approved