A206790 - OEIS

%I #7 Jul 17 2014 16:43:58

%S 4,16,61,232,883,3361,12793,48694,185344,705475,2685250,10220869,

%T 38903701,148079185,563633908,2145360148,8165885869,31081817236,

%U 118306743223,450311041525,1714019240113,6524072662150,24832582450012

%N Number of nX1 0..3 arrays avoiding the pattern z z+1 z in any row, column, diagonal or antidiagonal

%C Column 1 of A206797

%H R. H. Hardin, <a href="/A206790/b206790.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 4*a(n-1) -a(n-2) +a(n-3).

%F Empirical: G.f.: -x*(4+x^2) / ( -1+4*x-x^2+x^3 ). - _R. J. Mathar_, Jul 17 2014

%e Some solutions for n=4

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

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

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

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

%K nonn

%O 1,1

%A _R. H. Hardin_, Feb 12 2012