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A202972 Number of n X n 0..1 arrays with every nonzero element less than or equal to at least two horizontal and vertical neighbors 0
1, 2, 17, 385, 31380, 8071997, 6330398606, 15305115754880, 113359928263133320, 2565928235760939767164, 177686302889022383527488349, 37653160193950657089306550224687, 24413727008012244865702150476410950284 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Diagonal of A202979

LINKS

Table of n, a(n) for n=1..13.

EXAMPLE

Some solutions for n=5

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

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

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

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

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

CROSSREFS

Sequence in context: A128159 A319591 A198405 * A085617 A152557 A015202

Adjacent sequences:  A202969 A202970 A202971 * A202973 A202974 A202975

KEYWORD

nonn

AUTHOR

R. H. Hardin Dec 26 2011

STATUS

approved

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Last modified June 22 11:17 EDT 2021. Contains 345375 sequences. (Running on oeis4.)