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A272974 T(n,k)=Number of nXk 0..1 arrays with exactly n+k-1 having value 1 and no three 1s forming an isosceles triangle. 1

%I

%S 1,1,1,1,0,1,1,1,1,1,1,0,0,0,1,1,0,0,0,0,1,1,0,0,0,0,0,1,1,0,3,0,0,3,

%T 0,1,1,0,0,0,0,0,0,0,1,1,0,2,0,0,0,0,2,0,1,1,0,0,0,0,0,0,0,0,0,1,1,0,

%U 2,0,4,0,0,4,0,2,0,1,1,0,0,0,0,0,0,0,0,0,0,0,1,1,0,2,0,2,0,0,0,0,2,0,2,0,1,1,0,0

%N T(n,k)=Number of nXk 0..1 arrays with exactly n+k-1 having value 1 and no three 1s forming an isosceles triangle.

%C Table starts

%C .1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1.1

%C .1.0.1.0.0.0.0.0.0.0.0.0.0.0.0.0

%C .1.1.0.0.0.3.0.2.0.2.0.2.0.2.0

%C .1.0.0.0.0.0.0.0.0.0.0.0.0.0

%C .1.0.0.0.0.0.0.4.0.2.0.0.0

%C .1.0.3.0.0.0.0.0.0.0.1.8

%C .1.0.0.0.0.0.0.0.0.3.0

%C .1.0.2.0.4.0.0.0.1

%C .1.0.0.0.0.0.0.1

%C .1.0.2.0.2.0.3

%C .1.0.0.0.0.1

%C .1.0.2.0.0

%C .1.0.0.0

%C .1.0.2

%C .1.0

%C .1

%H R. H. Hardin, <a href="/A272974/b272974.txt">Table of n, a(n) for n = 1..143</a>

%F Row n extended:

%F n=2: 1 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

%F n=3: 1 1 0 0 0 3 0 2 0 2 0 2 0 2 0 2 0 2 0 2 0 2

%F n=4: 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

%F n=5: 1 0 0 0 0 0 0 4 0 2 0 0 0 0 0

%F n=6: 1 0 3 0 0 0 0 0 0 0 1 8 0

%e All solutions for n=3 k=6

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

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

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

%K nonn,tabl

%O 1,31

%A _R. H. Hardin_, May 11 2016

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Last modified December 7 07:55 EST 2021. Contains 349571 sequences. (Running on oeis4.)