A197674 - OEIS

%I #5 Mar 31 2012 12:36:30

%S 4,16,57,202,721,2557,8930,31326,110217,387627,1363559,4796483,

%T 16870356,59337438,208705786,734075168,2581952574,9081465807,

%U 31942103268,112349483389,395165129695,1389908311471,4888703531124,17194963235219

%N Number of nX3 0..4 arrays with each element x equal to the number its horizontal and vertical neighbors equal to 2,0,1,0,1 for x=0,1,2,3,4

%C Every 0 is next to 0 2's, every 1 is next to 1 0's, every 2 is next to 2 1's, every 3 is next to 3 0's, every 4 is next to 4 1's

%C Column 3 of A197679

%H R. H. Hardin, <a href="/A197674/b197674.txt">Table of n, a(n) for n = 1..200</a>

%F Empirical: a(n) = 4*a(n-1) +a(n-2) -6*a(n-3) -14*a(n-4) +29*a(n-6) -18*a(n-7) -29*a(n-8) -46*a(n-9) +79*a(n-10) +199*a(n-11) +62*a(n-12) -91*a(n-13) -228*a(n-14) -70*a(n-15) +92*a(n-16) +71*a(n-17) +30*a(n-18) -35*a(n-19) -3*a(n-20) -3*a(n-21) -18*a(n-22) +4*a(n-23) +a(n-24) -a(n-25) +a(n-26)

%e Some solutions for n=4

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

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

%e ..1..4..1....0..0..3....3..0..1....0..3..0....1..0..3....1..0..3....0..0..1

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

%K nonn

%O 1,1

%A _R. H. Hardin_ Oct 17 2011