A237550 - OEIS

%I #8 Oct 22 2018 17:39:41

%S 81,312,1240,4752,19128,72736,290112,1110080,4459296,16979328,

%T 67827328,259259648,1040224128,3964054016,15850143744,60545315840,

%U 242745766400,925519968256,3702814799872,14138549342208,56660164196352

%N Number of (n+1) X (1+1) 0..2 arrays with the maximum minus the upper median of every 2 X 2 subblock differing from its horizontal and vertical neighbors by exactly one.

%H R. H. Hardin, <a href="/A237550/b237550.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 192*a(n-4) + 608*a(n-6) + 400*a(n-8) for n>9.

%F Empirical g.f.: x*(81 + 312*x + 1240*x^2 + 4752*x^3 + 3576*x^4 + 12832*x^5 + 2784*x^6 + 8000*x^7 + 400*x^8) / (1 - 192*x^4 - 608*x^6 - 400*x^8). - _Colin Barker_, Oct 22 2018

%e Some solutions for n=5:

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

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

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

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

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

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

%Y Column 1 of A237557.

%K nonn

%O 1,1

%A _R. H. Hardin_, Feb 09 2014