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A191551
Number of n X n symmetric binary matrices with each 1 adjacent to no more than 1 diagonally or antidiagonally neighboring 1
1
2, 8, 33, 297, 4032, 91392, 3461143, 214272233, 22066261672, 3754762272000, 1054824912314030, 490291568481195135, 376674319103188012304, 478415094920126210097672, 1004588343161199901448153154
OFFSET
1,1
LINKS
EXAMPLE
Some solutions for n=4
..1..1..1..1....0..0..0..1....1..0..1..0....1..1..0..1....0..0..0..0
..1..0..0..0....0..1..0..0....0..0..1..1....1..1..0..0....0..1..0..0
..1..0..0..0....0..0..1..0....1..1..0..0....0..0..0..1....0..0..0..0
..1..0..0..1....1..0..0..0....0..1..0..0....1..0..1..0....0..0..0..1
CROSSREFS
Sequence in context: A236382 A269890 A005040 * A263627 A172448 A268601
KEYWORD
nonn
AUTHOR
R. H. Hardin Jun 05 2011
STATUS
approved