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%I #7 Apr 19 2020 23:44:26
%S 0,5,84,4133,317966,55491832,19876401224,15564645769042,
%T 26617222097087230,99905925686618815012,832547140418699137884096,
%U 15355865014207234684746438192,632296902429868672596327438625296
%N Number of n X n binary arrays with some element plus some horizontally or antidiagonally adjacent neighbor totalling two exactly once.
%C Diagonal of A268886.
%H R. H. Hardin, <a href="/A268880/b268880.txt">Table of n, a(n) for n = 1..26</a>
%e Some solutions for n=4
%e ..1..1..0..0. .0..1..0..1. .0..0..0..1. .0..0..1..0. .0..0..0..0
%e ..0..0..0..0. .0..1..0..0. .0..0..1..0. .1..0..1..0. .0..1..0..1
%e ..0..0..0..0. .1..0..0..1. .1..0..1..0. .0..0..0..0. .0..1..0..0
%e ..0..0..0..1. .0..0..0..1. .1..0..0..1. .1..0..1..1. .1..0..1..0
%Y Cf. A268886.
%K nonn
%O 1,2
%A _R. H. Hardin_, Feb 15 2016