A184097 T(n,k)=Half the number of nXk toroidal binary arrays with each element having the sum of its vertical neighbors equal to the sum of its horizontal neighbors

1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1, 2, 7, 2, 1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 18, 1, 2, 1, 1, 1, 7, 1, 1, 7, 1, 1, 1, 2, 1, 2, 31, 2, 1, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 7, 18, 1, 98, 1, 18, 7, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 2, 1, 2, 127, 2, 1, 2, 1, 2, 1, 1, 1, 7, 1, 31, 7, 1, 1, 7, 31, 1, 7

Offset

1,5

Comments

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

Table starts

.1.1.1..1..1..1...1...1...1....1.1..1.1...1..1...1.1...1.1....1...1.1.1...1..1

.1.2.1..2..1..2...1...2...1....2.1..2.1...2..1...2.1...2.1....2...1.2.1...2..1

.1.1.7..1..1..7...1...1...7....1.1..7.1...1..7...1.1...7.1....1...7.1.1...7..1

.1.2.1.18..1..2...1..18...1....2.1.18.1...2..1..18.1...2.1...18...1.2.1..18..1

.1.1.1..1.31..1...1...1...1...31.1..1.1...1.31...1.1...1.1...31...1.1.1...1.31

.1.2.7..2..1.98...1...2...7....2.1.98.1...2..7...2.1..98.1....2...7.2.1..98..1

.1.1.1..1..1..1.127...1...1....1.1..1.1.127..1...1.1...1.1....1.127.1.1...1..1

.1.2.1.18..1..2...1.450...1....2.1.18.1...2..1.450.1...2.1...18...1.2.1.450..1

.1.1.7..1..1..7...1...1.511....1.1..7.1...1..7...1.1.511.1....1...7.1.1...7..1

.1.2.1..2.31..2...1...2...1.1922.1..2.1...2.31...2.1...2.1.1922...1.2.1...2.31

Links

R. H. Hardin, Table of n, a(n) for n = 1..840

Example

Some solutions for 9X3
..1..0..0....0..0..1....1..1..0....0..1..0....1..0..1....1..1..0....0..0..1
..0..1..0....0..1..0....1..0..1....1..0..0....1..1..0....0..1..1....1..0..0
..0..0..1....1..0..0....0..1..1....0..0..1....0..1..1....1..0..1....0..1..0
..1..0..0....0..0..1....1..1..0....0..1..0....1..0..1....1..1..0....0..0..1
..0..1..0....0..1..0....1..0..1....1..0..0....1..1..0....0..1..1....1..0..0
..0..0..1....1..0..0....0..1..1....0..0..1....0..1..1....1..0..1....0..1..0
..1..0..0....0..0..1....1..1..0....0..1..0....1..0..1....1..1..0....0..0..1
..0..1..0....0..1..0....1..0..1....1..0..0....1..1..0....0..1..1....1..0..0
..0..0..1....1..0..0....0..1..1....0..0..1....0..1..1....1..0..1....0..1..0

Crossrefs

Sequence in context: A214403 A261527 A292436 * A345932 A205399 A135303

Adjacent sequences: A184094 A184095 A184096 * A184098 A184099 A184100

Keyword

nonn,tabl

Author

R. H. Hardin Jan 09 2011

Status

approved