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A272951
Number of n X n 0..1 arrays with exactly n+n-2 having value 1 and no three 1's forming an isosceles right triangle.
0
1, 6, 24, 60, 768, 7468, 131056, 4614732
OFFSET
1,2
COMMENTS
Diagonal of A272958.
EXAMPLE
Some solutions for n=5
..0..0..0..0..1. .1..0..1..0..0. .1..0..1..1..0. .0..1..0..0..1
..1..0..0..0..0. .1..0..0..0..1. .0..0..0..0..1. .0..0..0..0..1
..1..0..0..1..1. .0..0..0..0..0. .0..0..0..0..0. .0..0..0..0..1
..1..0..0..0..0. .1..0..0..0..1. .0..1..0..0..1. .0..0..1..1..0
..0..1..0..0..1. .1..0..1..0..0. .0..0..1..1..0. .1..1..0..0..0
CROSSREFS
Cf. A272958.
Sequence in context: A371175 A292889 A366546 * A358081 A371045 A371159
KEYWORD
nonn
AUTHOR
R. H. Hardin, May 11 2016
STATUS
approved