A235949 - OEIS

%I #8 Oct 20 2018 10:22:38

%S 905,1372,1494,1780,2478,3504,4884,6888,9816,13920,19554,27600,39296,

%T 55680,78216,110400,157184,222720,312864,441600,628736,890880,1251456,

%U 1766400,2514944,3563520,5005824,7065600,10059776,14254080,20023296

%N Number of (n+1) X (3+1) 0..2 arrays colored with the upper median value of each 2 X 2 subblock.

%H R. H. Hardin, <a href="/A235949/b235949.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 4*a(n-4) for n>13.

%F Empirical g.f.: x*(905 + 1372*x + 1494*x^2 + 1780*x^3 - 1142*x^4 - 1984*x^5 - 1092*x^6 - 232*x^7 - 96*x^8 - 96*x^9 + 18*x^10 + 48*x^11 + 32*x^12) / ((1 - 2*x^2)*(1 + 2*x^2)). - _Colin Barker_, Oct 20 2018

%e Some solutions for n=5:

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

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

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

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

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

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

%Y Column 3 of A235954.

%K nonn

%O 1,1

%A _R. H. Hardin_, Jan 17 2014