login
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
OFFSET
1,2
COMMENTS
Diagonal of A202979
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
KEYWORD
nonn
AUTHOR
R. H. Hardin Dec 26 2011
STATUS
approved