A227160 - OEIS

A227160

Number of n X n 0,1 arrays indicating 2X2 subblocks of some larger (n+1)X(n+1) binary array having a sum of one or less, with rows and columns of the latter in lexicographically nondecreasing order

2, 8, 62, 944, 37012, 3754497, 1009485843, 732609096798

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OFFSET

1,1

COMMENTS

Diagonal of A227165

LINKS

Table of n, a(n) for n=1..8.

EXAMPLE

Some solutions for n=4

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

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

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

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

CROSSREFS

Sequence in context: A230824 A006245 A202751 * A191604 A009271 A153539

Adjacent sequences: A227157 A227158 A227159 * A227161 A227162 A227163

KEYWORD

nonn

AUTHOR

R. H. Hardin Jul 03 2013

STATUS

approved