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A221505 Number of nX3 arrays of occupancy after each element moves to some horizontal, diagonal or antidiagonal neighbor, without consecutive moves in the same direction.

%I A221505 #7 Jul 24 2025 19:41:00
%S A221505 0,44,664,12495,221614,4010052,72195950,1301644004,23457033692,
%T A221505 422775316892,7619575554956,137327198061432,2475032964645724,
%U A221505 44607285582888084,803952693936738644,14489560929396894421
%N A221505 Number of nX3 arrays of occupancy after each element moves to some horizontal, diagonal or antidiagonal neighbor, without consecutive moves in the same direction.
%C A221505 Column 3 of A221507
%H A221505 R. H. Hardin, <a href="/A221505/b221505.txt">Table of n, a(n) for n = 1..20</a>
%e A221505 Some solutions for n=3
%e A221505 ..0..0..0....0..3..0....0..4..0....1..1..0....0..1..1....0..1..0....0..0..0
%e A221505 ..2..5..1....2..1..0....1..2..0....1..2..1....1..4..1....1..3..2....0..4..2
%e A221505 ..0..1..0....1..2..0....0..0..2....0..3..0....0..1..0....0..2..0....1..2..0
%K A221505 nonn
%O A221505 1,2
%A A221505 _R. H. Hardin_ Jan 18 2013