A093440 Number of n X n symmetric binary matrices with each element either the sum mod 2 of its diagonal neighbors or the sum mod 2 of its antidiagonal neighbors

1, 4, 20, 100, 720, 7920, 156960, 4978909, 162844632, 9658482053, 917891979225, 113051563311936, 21440096665285608, 6394092372716939840, 2723634378368868283440, 1747667851609071536512000

Offset

1,2

Links

R. H. Hardin, Table of n, a(n) for n = 1..21

Example

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

Crossrefs

Sequence in context: A105480 A242156 A186369 * A168606 A229135 A226198

Adjacent sequences: A093437 A093438 A093439 * A093441 A093442 A093443

Keyword

nonn

Author

R. H. Hardin Jun 26 2011

Status

approved