A183519 - OEIS

%I #5 Mar 31 2012 12:35:52

%S 3,9,31,95,309,911,2803,8673,26619,81959,252477,777327,2393627,

%T 7371657,22698115,69895583,215235669,662786215,2040959827,6284869089,

%U 19353386043,59596135287,183518286189,565119695167,1740209766219,5358741068409

%N Number of nX2 0..2 arrays with each element equal to either the sum mod 3 of its horizontal and vertical neighbors or the sum mod 3 of its diagonal and antidiagonal neighbors

%C Column 2 of A183526

%H R. H. Hardin, <a href="/A183519/b183519.txt">Table of n, a(n) for n = 1..200</a>

%F Empirical: a(n)=3*a(n-1)+6*a(n-3)-16*a(n-4)+7*a(n-6)-25*a(n-7)-44*a(n-9)+102*a(n-10)-184*a(n-12)+520*a(n-13)+320*a(n-15)-720*a(n-16)+640*a(n-18)-1600*a(n-19)

%e Some solutions for 3X2

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

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

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

%K nonn

%O 1,1

%A _R. H. Hardin_ Jan 05 2011