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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
1, 4, 20, 100, 720, 7920, 156960, 4978909, 162844632, 9658482053, 917891979225, 113051563311936, 21440096665285608, 6394092372716939840, 2723634378368868283440, 1747667851609071536512000 (list; graph; refs; listen; history; text; internal format)
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

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Last modified March 21 04:59 EDT 2019. Contains 321364 sequences. (Running on oeis4.)