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A269070 Number of n X 3 binary arrays with some element plus some horizontally, diagonally or antidiagonally adjacent neighbor totalling two not more than once. 1

%I #7 Jan 18 2019 15:00:33

%S 7,27,123,537,2343,10167,43959,189465,814359,3491691,14937987,

%T 63778065,271799175,1156345287,4911870063,20834207313,88251723687,

%U 373358554971,1577691954507,6659543294313,28081651307943,118299768626103

%N Number of n X 3 binary arrays with some element plus some horizontally, diagonally or antidiagonally adjacent neighbor totalling two not more than once.

%H R. H. Hardin, <a href="/A269070/b269070.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 10*a(n-1) - 31*a(n-2) + 24*a(n-3) + 21*a(n-4) - 18*a(n-5) - 9*a(n-6).

%F Empirical g.f.: x*(7 - 43*x + 70*x^2 - 24*x^3 - 9*x^4 - 9*x^5) / (1 - 5*x + 3*x^2 + 3*x^3)^2. - _Colin Barker_, Jan 18 2019

%e Some solutions for n=4:

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

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

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

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

%Y Column 3 of A269075.

%K nonn

%O 1,1

%A _R. H. Hardin_, Feb 19 2016

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Last modified March 28 14:21 EDT 2024. Contains 371254 sequences. (Running on oeis4.)