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A193480 Number of n X n symmetric 0..1 arrays with each element equal to the product mod 2 of two of its horizontal and vertical neighbors 1
0, 2, 4, 26, 240, 4063, 110576, 5046694, 390350577, 51445991632, 11496127271424, 4348804724288989, 2784306483759192151, 3019459887601073667024, 5548682373331641079067391, 17274304412990968236505863156 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..19

EXAMPLE

Some solutions for 4X4

..0..0..1..1....1..1..1..1....1..1..0..0....1..1..1..1....1..1..1..0

..0..0..1..1....1..0..0..1....1..1..1..1....1..1..1..1....1..1..1..0

..1..1..1..0....1..0..0..1....0..1..1..1....1..1..1..1....1..1..1..1

..1..1..0..0....1..1..1..1....0..1..1..1....1..1..1..1....0..0..1..1

CROSSREFS

Sequence in context: A019034 A091759 A262067 * A032076 A182146 A218077

Adjacent sequences:  A193477 A193478 A193479 * A193481 A193482 A193483

KEYWORD

nonn

AUTHOR

R. H. Hardin Jul 27 2011

STATUS

approved

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Last modified December 9 03:42 EST 2021. Contains 349625 sequences. (Running on oeis4.)