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 A210269 Half the number of (n+1) X 2 0..2 arrays with every 2 X 2 subblock having two or three distinct clockwise edge differences. 1

%I

%S 35,273,2130,16620,129684,1011912,7895856,61610640,480742176,

%T 3751187136,29270169408,228392449152,1782125347584,13905760747776,

%U 108505376592384,846657508568064,6606390939571200,51549062997460992,402232613876871168

%N Half the number of (n+1) X 2 0..2 arrays with every 2 X 2 subblock having two or three distinct clockwise edge differences.

%C Column 1 of A210276.

%H R. H. Hardin, <a href="/A210269/b210269.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 8*a(n-1) - 12*a(n-3).

%F Empirical g.f.: x*(35 - 7*x - 54*x^2) / (1 - 8*x + 12*x^3). - _Colin Barker_, Jul 15 2018

%e Some solutions for n=4:

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

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

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

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

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

%Y Cf. A210276.

%K nonn

%O 1,1

%A _R. H. Hardin_, Mar 19 2012

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Last modified December 2 13:48 EST 2021. Contains 349444 sequences. (Running on oeis4.)