Reminder: The OEIS is hiring a new managing editor, and the application deadline is January 26.
%I #8 May 26 2014 00:36:15
%S 870,29022,1093244,40007284,1514539540,55445403092,2098930772556,
%T 76841262200636,2908798092956244,106493580023151652,
%U 4031150148001496108,147588444595292151484,5586558915888288059252,204541422493382617854660
%N Number of (n+1) X 4 0..3 arrays with the number of equal 2 X 2 subblock diagonal pairs and equal antidiagonal pairs differing from each horizontal or vertical neighbor, and new values 0..3 introduced in row major order.
%C Column 3 of A205431.
%H R. H. Hardin, <a href="/A205426/b205426.txt">Table of n, a(n) for n = 1..210</a>
%F Empirical: a(n) = a(n-1) +1437*a(n-2) -1436*a(n-3) -73559*a(n-4) +137575*a(n-5) +1288600*a(n-6) -3105933*a(n-7) -2093681*a(n-8) +2368404*a(n-9) -65489997*a(n-10) +236894949*a(n-11) +346457313*a(n-12) -1484643168*a(n-13) -128120832*a(n-14) +2924517312*a(n-15) -2128639824*a(n-16) +1119744*a(n-17) +2855067264*a(n-18) -4073488704*a(n-19) +1273568832*a(n-20) +272097792*a(n-21) for n>22.
%e Some solutions for n=4:
%e ..0..0..0..0....0..0..0..0....0..1..0..2....0..0..1..0....0..0..1..1
%e ..0..0..1..2....0..1..1..0....2..1..1..2....0..1..0..3....1..0..1..0
%e ..2..0..1..1....1..0..1..2....2..2..2..3....3..1..1..1....1..0..0..1
%e ..1..1..2..2....1..1..0..1....1..3..2..0....1..3..2..1....3..1..1..1
%e ..3..1..3..2....0..0..2..1....3..3..0..2....1..2..3..3....1..3..1..1
%K nonn
%O 1,1
%A _R. H. Hardin_, Jan 27 2012