A210071 - OEIS

%I #5 Mar 31 2012 12:37:31

%S 313,7653,183628,4437262,107248254,2593403383,62718516080,

%T 1516857228897,36686107681359,887282513364238,21459693101245663,

%U 519021821704689384,12553011852527384605,303605996524472486222,7342987441944334048364

%N 1/4 the number of (n+1)X3 0..3 arrays with every 2X2 subblock having one or three distinct clockwise edge differences

%C Column 2 of A210077

%H R. H. Hardin, <a href="/A210071/b210071.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 40*a(n-1) -410*a(n-2) +162*a(n-3) +13887*a(n-4) -37312*a(n-5) -114069*a(n-6) +441850*a(n-7) +251010*a(n-8) -1865698*a(n-9) +353991*a(n-10) +3283497*a(n-11) -1672828*a(n-12) -2287997*a(n-13) +1529824*a(n-14) +444317*a(n-15) -334882*a(n-16) -35990*a(n-17) +21286*a(n-18) +648*a(n-19) -288*a(n-20)

%e Some solutions for n=4

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

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

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

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

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

%K nonn

%O 1,1

%A _R. H. Hardin_ Mar 17 2012