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 A318039 Number of nX2 0..1 arrays with every element unequal to 0, 2, 3 or 4 horizontally, vertically or antidiagonally adjacent elements, with upper left element zero. 1

%I #4 Aug 13 2018 14:29:41

%S 1,2,2,3,6,17,46,124,341,947,2630,7299,20261,56255,156198,433692,

%T 1204166,3343438,9283267,25775570,71567465,198711506,551734848,

%U 1531926101,4253488019,11810073810,32791403883,91047370757,252798683167

%N Number of nX2 0..1 arrays with every element unequal to 0, 2, 3 or 4 horizontally, vertically or antidiagonally adjacent elements, with upper left element zero.

%C Column 2 of A318045.

%H R. H. Hardin, <a href="/A318039/b318039.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 3*a(n-1) -a(n-2) +a(n-3) +a(n-4) -2*a(n-5) -a(n-6) for n>7

%e All solutions for n=5

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

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

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

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

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

%Y Cf. A318045.

%K nonn

%O 1,2

%A _R. H. Hardin_, Aug 13 2018

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Last modified June 13 16:27 EDT 2024. Contains 373389 sequences. (Running on oeis4.)