A236324 - OEIS

%I #8 Oct 21 2018 13:45:48

%S 32,44,60,92,156,236,332,524,860,1276,1852,2956,4716,6956,10364,16540,

%T 25820,38188,57996,91980,141468,210748,323964,509388,776620,1166956,

%U 1805244,2814172,4273436,6473068,10035148,15530124,23566812,35927420

%N Number of (n+1) X (2+1) 0..1 arrays colored with the sum of the upper and lower median values of each 2 X 2 subblock.

%H R. H. Hardin, <a href="/A236324/b236324.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = a(n-3) + 4*a(n-4) for n>5.

%F Empirical g.f.: 4*x*(8 + 11*x + 15*x^2 + 15*x^3 - 4*x^4) / (1 - x^3 - 4*x^4). - _Colin Barker_, Oct 21 2018

%e Some solutions for n=5:

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

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

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

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

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

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

%K nonn

%O 1,1

%A _R. H. Hardin_, Jan 22 2014