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Number of nX4 0..1 arrays with exactly n+4-2 having value 1 and no three 1s forming an isosceles right triangle.
1

%I #4 May 11 2016 14:52:51

%S 4,21,24,60,210,637,1840,5792,18556,54034,160246,499140,1501706,

%T 4627363,13954490,43064736,131174878,399170874,1222825766,3739040310,

%U 11456400210,35068696769,107362206600,329271410590,1009129910706,3096269613087

%N Number of nX4 0..1 arrays with exactly n+4-2 having value 1 and no three 1s forming an isosceles right triangle.

%C Column 4 of A272958.

%H R. H. Hardin, <a href="/A272954/b272954.txt">Table of n, a(n) for n = 1..110</a>

%e Some solutions for n=5

%e ..0..1..1..0. .1..0..0..1. .0..0..1..1. .0..1..1..1. .1..0..1..0

%e ..1..0..0..1. .0..1..1..0. .0..0..0..0. .0..0..0..0. .0..0..0..1

%e ..0..0..0..0. .0..0..0..0. .1..0..0..1. .0..0..1..0. .0..0..0..1

%e ..1..0..0..1. .0..0..0..0. .1..0..1..0. .0..0..0..1. .0..0..1..0

%e ..0..1..0..0. .1..0..1..1. .1..0..0..0. .0..1..0..1. .1..1..0..0

%Y Cf. A272958.

%K nonn

%O 1,1

%A _R. H. Hardin_, May 11 2016