A190340 Number of (n+1)X(n+1) symmetric binary matrices without the pattern 1 1 antidiagonally

4, 12, 72, 720, 10800, 259200, 10368000, 673920000, 70087680000, 11774730240000, 3214501355520000, 1420809599139840000, 1014458053785845760000, 1171699052122651852800000, 2191077227469358964736000000

Offset

1,1

Links

R. H. Hardin, Table of n, a(n) for n = 1..47

Example

Some solutions for 3X3
..1..0..1....0..0..1....0..0..1....0..0..0....1..0..0....1..0..1....0..0..0
..0..0..0....0..0..0....0..0..0....0..1..0....0..1..0....0..0..0....0..0..0
..1..0..0....1..0..1....1..0..0....0..0..1....0..0..0....1..0..1....0..0..0

Crossrefs

Sequence in context: A166746 A052558 A369285 * A232325 A291487 A133666

Adjacent sequences: A190337 A190338 A190339 * A190341 A190342 A190343

Keyword

nonn

Author

R. H. Hardin May 09 2011

Status

approved