A206688 - OEIS

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

%S 2,36,176,916,4704,24492,127008,660888,3436488,17884080,93059016,

%T 484334480,2520695968,13119605656,68284077520,355405952496,

%U 1849822022856,9628019156288,50112266984832,260826450827576,1357560738338768

%N Number of nX4 0..3 arrays with no element equal to another within two positions in the same row or column, and new values 0..3 introduced in row major order

%C Column 4 of A206692

%H R. H. Hardin, <a href="/A206688/b206688.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 8*a(n-1) -8*a(n-2) -48*a(n-3) +48*a(n-4) +140*a(n-5) +67*a(n-6) -968*a(n-7) +1564*a(n-8) -586*a(n-9) -1008*a(n-10) -32*a(n-11) +1304*a(n-12) +80*a(n-13) -512*a(n-14) for n>15

%e Some solutions for n=4

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

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

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

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

%K nonn

%O 1,1

%A _R. H. Hardin_ Feb 11 2012