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A206014 Number of (n+1) X 2 0..3 arrays with the number of clockwise edge increases in every 2 X 2 subblock unequal to the number of counterclockwise edge increases. 1

%I

%S 104,680,4440,29000,189400,1237000,8079000,52765000,344615000,

%T 2250725000,14699775000,96006125000,627028375000,4095203125000,

%U 26746299375000,174683528125000,1140880634375000,7451238453125000,48664998609375000

%N Number of (n+1) X 2 0..3 arrays with the number of clockwise edge increases in every 2 X 2 subblock unequal to the number of counterclockwise edge increases.

%C Column 1 of A206021.

%H R. H. Hardin, <a href="/A206014/b206014.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 5*a(n-1) + 10*a(n-2).

%F Empirical g.f.: 8*x*(13 + 20*x) / (1 - 5*x - 10*x^2). - _Colin Barker_, Jun 13 2018

%e Some solutions for n=3:

%e ..3..0....0..2....1..0....1..0....1..1....3..0....1..3....1..0....0..1....2..0

%e ..1..0....1..1....3..3....1..2....2..3....1..0....0..3....2..3....0..2....1..0

%e ..3..3....3..2....2..0....3..2....0..3....1..2....0..1....2..1....1..1....1..3

%e ..0..1....0..0....2..3....3..0....1..1....3..2....3..3....2..3....0..2....0..0

%Y Cf. A206021.

%K nonn

%O 1,1

%A _R. H. Hardin_, Feb 02 2012

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Last modified February 5 11:56 EST 2023. Contains 360084 sequences. (Running on oeis4.)