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A236942 Number of (n+1) X (1+1) 0..3 arrays with the maximum of every 2 X 2 subblock equal. 1

%I

%S 256,2796,30698,357316,4195956,50119046,601976968,7271574636,

%T 88068458546,1068829320076,12986262880788,157905941911406,

%U 1920929508184336,23375169249987756,284496769631574458,3462985011143368276

%N Number of (n+1) X (1+1) 0..3 arrays with the maximum of every 2 X 2 subblock equal.

%H R. H. Hardin, <a href="/A236942/b236942.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 16*a(n-1) - 650*a(n-3) + 596*a(n-4) + 5184*a(n-5) - 1365*a(n-6) - 3780*a(n-7).

%F Empirical g.f.: 2*x*(128 - 650*x - 7019*x^2 + 16274*x^3 + 71862*x^4 - 28035*x^5 - 56700*x^6) / ((1 - x)*(1 - 3*x - 3*x^2)*(1 - 5*x - 20*x^2)*(1 - 7*x - 63*x^2)). - _Colin Barker_, Oct 21 2018

%e Some solutions for n=3:

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

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

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

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

%Y Column 1 of A236949.

%K nonn

%O 1,1

%A _R. H. Hardin_, Feb 01 2014

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Last modified September 22 04:49 EDT 2021. Contains 347605 sequences. (Running on oeis4.)