cp's OEIS Frontend

A221335 Number of nX3 arrays of occupancy after each element stays put or moves to some king-move neighbor, with every occupancy equal to zero or two.

%I A221335 #7 Jul 23 2025 01:50:49
%S A221335 0,20,0,790,0,34042,0,1470618,0,63526554,0,2744129114,0,118536728562,
%T A221335 0,5120367434418,0,221181729631882,0,9554266491058090,0,
%U A221335 412710429318366178,0,17827626812331482594,0,770090248640353835354,0
%N A221335 Number of nX3 arrays of occupancy after each element stays put or moves to some king-move neighbor, with every occupancy equal to zero or two.
%C A221335 Column 3 of A221337
%H A221335 R. H. Hardin, <a href="/A221335/b221335.txt">Table of n, a(n) for n = 1..30</a>
%F A221335 Empirical: a(n) = 66*a(n-2) -1131*a(n-4) +6726*a(n-6) -18808*a(n-8) +27860*a(n-10) -19388*a(n-12) +3240*a(n-14)
%K A221335 nonn
%O A221335 1,2
%A A221335 _R. H. Hardin_ Jan 11 2013