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A206102 Number of (n+1) X 2 0..3 arrays with the number of clockwise edge increases in 2 X 2 subblocks nondecreasing, and counterclockwise edge increases nonincreasing, rightwards and downwards. 1

%I #7 Dec 11 2015 11:59:08

%S 256,2292,15564,95408,574364,3472540,21122008,129099360,792188532,

%T 4877980340,30132023264,186677124664,1159672904860,7222244911020,

%U 45083174298216,282019092305744,1767599836030724,11098250929281124

%N Number of (n+1) X 2 0..3 arrays with the number of clockwise edge increases in 2 X 2 subblocks nondecreasing, and counterclockwise edge increases nonincreasing, rightwards and downwards.

%C Column 1 of A206109.

%H R. H. Hardin, <a href="/A206102/b206102.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 16*a(n-1) - 87*a(n-2) + 174*a(n-3) - 15*a(n-4) - 420*a(n-5) + 607*a(n-6) - 346*a(n-7) + 72*a(n-8) for n>10.

%e Some solutions for n=4:

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

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

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

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

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

%K nonn

%O 1,1

%A _R. H. Hardin_, Feb 03 2012

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Last modified March 28 22:04 EDT 2024. Contains 371254 sequences. (Running on oeis4.)