A205640 - OEIS

%I #7 Oct 09 2015 04:26:22

%S 17111320,962953968,163624211124,46738310925116,14510023537151756,

%T 4561749663096542724,1438784646024287898832,454396326607940446880368,

%U 143606330702285831573137588,45403346502622885237604211100

%N Number of (n+1)X7 0..3 arrays with every 2 X 2 subblock having the number of clockwise edge increases equal to the number of counterclockwise edge increases in its adjacent leftward and upward neighbors.

%C Column 6 of A205642.

%H R. H. Hardin, <a href="/A205640/b205640.txt">Table of n, a(n) for n = 1..18</a>

%e Some solutions for n=4:

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

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

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

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

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

%K nonn

%O 1,1

%A _R. H. Hardin_, Jan 29 2012