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 A268621 Number of n X n 0..2 arrays with some element plus some horizontally or vertically adjacent neighbor totaling two no more than once. 1

%I

%S 3,42,1086,55452,6000978,1430057208,767057092212,938662461734076,

%T 2643885168776274078,17245474696462104041796,

%U 261641272761781630830646332,9262823664147270920479995625968,767111588793900754143144516979246884

%N Number of n X n 0..2 arrays with some element plus some horizontally or vertically adjacent neighbor totaling two no more than once.

%C Diagonal of A268628.

%H R. H. Hardin, <a href="/A268621/b268621.txt">Table of n, a(n) for n = 1..14</a>

%e Some solutions for n=4

%e ..2..1..2..2. .0..0..0..0. .0..0..1..0. .2..1..0..0. .1..1..0..0

%e ..1..0..1..2. .0..1..1..0. .0..0..0..1. .1..0..0..0. .2..2..1..0

%e ..2..1..2..1. .1..0..0..1. .1..0..1..2. .0..1..0..0. .2..2..2..1

%e ..2..2..2..0. .0..0..1..0. .0..1..2..2. .0..0..0..1. .2..2..1..0

%Y Cf. A268628.

%K nonn

%O 1,1

%A _R. H. Hardin_, Feb 09 2016

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Last modified May 22 06:54 EDT 2022. Contains 353933 sequences. (Running on oeis4.)