A227120 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 zero, with rows and columns of the latter in lexicographically nondecreasing order

2, 7, 33, 295, 5820, 241783, 21458929, 4109192774, 1709864974106

Offset

1,1

Comments

Diagonal of A227125

Links

Table of n, a(n) for n=1..9.

Example

Some solutions for n=4
..0..0..0..0....1..0..0..0....0..0..0..0....1..1..1..1....0..0..0..0
..0..0..1..1....0..0..0..0....0..1..1..1....1..1..1..1....0..0..1..1
..0..1..1..1....0..0..1..1....0..1..1..1....1..1..1..1....0..0..1..1
..0..0..1..0....0..0..1..1....0..1..1..0....0..0..0..0....0..1..0..0

Crossrefs

Sequence in context: A350758 A241767 A222940 * A353343 A376055 A023053

Adjacent sequences: A227117 A227118 A227119 * A227121 A227122 A227123

Keyword

nonn

Author

R. H. Hardin Jul 01 2013

Status

approved