%I #7 Mar 13 2017 00:21:44
%S 1,1,2,8,40,495,7425,140429,3014206,73238115,2000005946
%N Number of nbead necklaces labeled with numbers n..n allowing reversal, with sum zero and first and second differences in n..n.
%C Diagonal of A208970.
%e Some solutions for n=5:
%e .2...3...3...1...2...1...1...2...2...1...2....0...2...2...3...3
%e .2...3...1....0...1....0...1...1....0....0...1....0....0....0...2...3
%e ..1....2....1...1....2....0....1....2....2...1....1....0....0....1....3....1
%e ..1....2....3....0....0....0....0....1...1....1....2....0....1....0....3....3
%e ..2....2....0....2....1....1....1....0....1....1....0....0....1....1...1....2
%K nonn
%O 1,3
%A _R. H. Hardin_, Mar 03 2012
