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%I #6 Mar 12 2017 23:50:00
%S 1,3,4,15,40,146,514,2032,8076,33310,138966,589618,2525494,10923868,
%T 47599638,208824200,921391230,4086463748,18206487792
%N Number of n-bead necklaces labeled with numbers -2..2 allowing reversal, with sum zero with no three beads in a row equal.
%C Column 2 of A209344.
%e Some solutions for n=10:
%e .-2...-2...-2...-2...-2...-2...-2...-2...-2...-2...-2...-2...-2...-2...-2...-2
%e .-1...-2...-2...-1...-2...-1...-2...-1....0...-1....0...-1...-2...-1....0...-1
%e .-2....2....0...-1....1...-1....2....0....1...-1....1....0....1...-2....0...-1
%e .-1...-2....0....1....0....1...-2...-1....0....1....0....2....2....0...-1....1
%e ..0...-1...-1....2...-1....1....1....0....2....2...-2....0....1....2....2....2
%e ..2....0....1....1....2....0....2....2....0....0....1...-1....2....1...-2....2
%e ..1....2....2....0...-1....0....0...-1...-1....0...-2....0...-2....1....0....0
%e ..1...-1...-1....1....0....2...-2....1....1...-2....1....2...-1...-1....0...-1
%e ..0....2....2....0....1...-2....1....2...-2....1....1...-1...-1....0....1...-2
%e ..2....2....1...-1....2....2....2....0....1....2....2....1....2....2....2....2
%K nonn
%O 1,2
%A _R. H. Hardin_, Mar 06 2012