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Number of n X 2 0..1 arrays with no element equal to more than four of its king-move neighbors, with the exception of exactly two elements, and with new values introduced in order 0 sequentially upwards.
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%I #8 Feb 20 2019 09:45:35

%S 0,0,1,6,33,166,792,3654,16455,72774,317367,1368608,5848140,24799548,

%T 104488541,437818374,1825747245,7581746154,31368531456,129358242306,

%U 531886946515,2181210602118,8923564277475,36428064156772,148413344768244

%N Number of n X 2 0..1 arrays with no element equal to more than four of its king-move neighbors, with the exception of exactly two elements, and with new values introduced in order 0 sequentially upwards.

%H R. H. Hardin, <a href="/A281930/b281930.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 6*a(n-1) - 3*a(n-2) - 14*a(n-3) - 21*a(n-4) - 12*a(n-5) - 4*a(n-6).

%F Empirical g.f.: x^3 / (1 - 3*x - 3*x^2 - 2*x^3)^2. - _Colin Barker_, Feb 20 2019

%e All solutions for n=4:

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

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

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

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

%Y Column 2 of A281936.

%K nonn

%O 1,4

%A _R. H. Hardin_, Feb 02 2017