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%I #6 Apr 21 2020 12:36:23
%S 1,6,24,60,768,7468,131056,4614732
%N 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.
%C Diagonal of A272958.
%e Some solutions for n=5
%e ..0..0..0..0..1. .1..0..1..0..0. .1..0..1..1..0. .0..1..0..0..1
%e ..1..0..0..0..0. .1..0..0..0..1. .0..0..0..0..1. .0..0..0..0..1
%e ..1..0..0..1..1. .0..0..0..0..0. .0..0..0..0..0. .0..0..0..0..1
%e ..1..0..0..0..0. .1..0..0..0..1. .0..1..0..0..1. .0..0..1..1..0
%e ..0..1..0..0..1. .1..0..1..0..0. .0..0..1..1..0. .1..1..0..0..0
%Y Cf. A272958.
%K nonn
%O 1,2
%A _R. H. Hardin_, May 11 2016
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