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A209025 Number of n-bead necklaces labeled with numbers -1..1 allowing reversal, with sum zero and first differences in -1..1.

%I A209025 #10 Mar 20 2017 09:51:04
%S A209025 1,1,1,2,2,4,6,13,21,45,83,181,362,794,1676,3703,8049,17925,39679,
%T A209025 88980,199308,449714,1015574,2303940,5234731,11931095,27239911,
%U A209025 62337821,142894336,328168558,754815704,1738888333,4011453913,9266702091,21433240903,49633242760
%N A209025 Number of n-bead necklaces labeled with numbers -1..1 allowing reversal, with sum zero and first differences in -1..1.
%H A209025 Andrew Howroyd, <a href="/A209025/b209025.txt">Table of n, a(n) for n = 1..100</a>
%e A209025 All solutions for n=6:
%e A209025 ..0...-1...-1...-1
%e A209025 ..0....0...-1....0
%e A209025 ..0....0....0....0
%e A209025 ..0....1....1....0
%e A209025 ..0....0....1....1
%e A209025 ..0....0....0....0
%Y A209025 Column 1 of A209032.
%K A209025 nonn
%O A209025 1,4
%A A209025 _R. H. Hardin_, Mar 04 2012
%E A209025 a(33)-a(36) from _Andrew Howroyd_, Mar 19 2017