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A187458
Number of (n+1)X(n+1) 0..1 arrays with all the 2X2 subblocks nonsingular and the array of 2X2 subblock determinants symmetric
1
6, 26, 144, 1272, 15192, 286392, 7648032, 314011868, 18986004296, 1725663296600, 237096836118080, 48071903199959400, 15027587384189632928, 6819730931931151055960, 4852231403635188536789728
OFFSET
1,1
COMMENTS
Column 1 of A187462
LINKS
EXAMPLE
Some solutions for 4X4
..1..1..0..1....1..0..1..1....0..1..0..1....1..0..1..1....1..0..1..0
..1..0..1..0....0..1..0..1....1..0..1..0....0..1..0..1....1..1..1..1
..0..1..0..1....1..0..1..1....1..1..0..1....1..0..1..1....1..0..1..0
..1..0..1..1....0..1..0..1....1..0..1..1....1..1..1..0....0..1..1..1
CROSSREFS
Sequence in context: A339685 A364744 A144037 * A100308 A352694 A049040
KEYWORD
nonn
AUTHOR
R. H. Hardin Mar 10 2011
STATUS
approved