A221765 - OEIS

%I #4 Jan 25 2013 05:05:41

%S 0,8,92,1042,12177,141177,1635606,18947791,219496141,2542689904,

%T 29455065560,341214041090,3952701351600,45789006180212,

%U 530430492884742,6144630449883102,71180832625348986,824575377747524532

%N Number of nX4 arrays of occupancy after each element moves to some horizontal or vertical neighbor, without 2-loops or left turns

%C Column 4 of A221768

%H R. H. Hardin, <a href="/A221765/b221765.txt">Table of n, a(n) for n = 1..41</a>

%e Some solutions for n=3

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

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

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

%K nonn

%O 1,2

%A _R. H. Hardin_ Jan 25 2013