%I #8 Feb 23 2018 09:51:30
%S 2,15,159,2191,31168,447343,6427791,92387812,1327953799,19087798375,
%T 274365294336,3943689122935,56686048473223,814797524429284,
%U 11711788424726319,168343648648695295,2419748633865949120
%N Number of n X 2 0..3 arrays with no occurrence of three equal elements in a row horizontally, vertically, diagonally or antidiagonally, and new values 0..3 introduced in row major order.
%C Column 2 of A204685.
%H R. H. Hardin, <a href="/A204679/b204679.txt">Table of n, a(n) for n = 1..210</a>
%F Empirical: a(n) = 14*a(n-1) +14*a(n-2) -124*a(n-3) -6*a(n-4) +90*a(n-5) -27*a(n-6) for n>8.
%F Empirical g.f.: x*(2 - 13*x - 79*x^2 + 3*x^3 + 140*x^4 - 57*x^5 - 21*x^6 + 9*x^7) / ((1 + x)*(1 + 3*x)*(1 - 3*x + x^2)*(1 - 15*x + 9*x^2)). - _Colin Barker_, Feb 23 2018
%e Some solutions for n=5:
%e ..0..1....0..0....0..1....0..0....0..0....0..0....0..0....0..0....0..1....0..0
%e ..1..0....1..0....1..0....0..1....0..0....0..0....0..0....0..0....0..1....0..0
%e ..0..0....0..1....0..0....1..2....1..2....1..1....1..1....1..2....1..0....1..1
%e ..0..1....1..0....2..1....0..1....1..3....2..3....0..1....2..1....1..0....1..2
%e ..1..0....0..1....0..2....0..0....2..0....3..0....1..2....1..0....2..3....2..0
%Y Cf. A204685.
%K nonn
%O 1,1
%A _R. H. Hardin_, Jan 18 2012
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