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%I #8 Jun 05 2018 14:35:37
%S 112,392,1400,5000,17800,63368,225704,803912,2863144,10197128,
%T 36317672,129347528,460677928,1640728328,5843540840,20812080200,
%U 74123322280,263994125192,940229020136,3348675314888,11926483984936,42476802576392
%N Number of (n+2) X 3 0..1 arrays with every 3 X 3 subblock having equal diagonal elements or equal antidiagonal elements, and new values 0..1 introduced in row major order.
%C Column 1 of A203923.
%H R. H. Hardin, <a href="/A203916/b203916.txt">Table of n, a(n) for n = 1..210</a>
%F Empirical: a(n) = 3*a(n-1) +6*a(n-3) +4*a(n-4).
%F Empirical g.f.: 8*x*(14 + 7*x + 28*x^2 + 16*x^3) / ((1 + 2*x^2)*(1 - 3*x - 2*x^2)). - _Colin Barker_, Jun 05 2018
%e Some solutions for n=3:
%e ..0..0..0....0..1..1....0..0..1....0..0..0....0..1..0....0..1..0....0..0..1
%e ..1..0..0....1..0..1....1..0..1....1..0..0....0..0..0....0..0..0....1..1..1
%e ..0..1..1....0..1..0....0..1..0....1..1..0....0..0..0....1..0..0....1..1..1
%e ..1..1..1....1..0..0....1..0..1....0..1..1....0..0..1....0..1..0....1..1..1
%e ..1..1..1....0..0..1....1..0..0....1..0..1....0..0..0....0..0..1....1..1..1
%Y Cf. A203923.
%K nonn
%O 1,1
%A _R. H. Hardin_, Jan 07 2012
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