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A208974
Number of 7-bead necklaces labeled with numbers -n..n allowing reversal, with sum zero and first and second differences in -n..n.
1
2, 15, 87, 371, 1185, 3186, 7425, 15658, 30368, 55222, 95087, 156612, 248194, 380753, 567639, 825586, 1174510, 1638724, 2246594, 3032025, 4033918, 5298001, 6876080, 8828154, 11221516, 14133153, 17648642, 21864897, 26888831, 32840460, 39851308
OFFSET
1,1
COMMENTS
Row 7 of A208970.
LINKS
EXAMPLE
Some solutions for n=5:
-5 -4 -3 -3 -1 -4 -3 -1 -4 -3 -3 -4 -4 -3 -2 -1
-3 -3 -3 -1 -1 -2 -3 -1 -2 -3 -2 -3 -4 -3 -1 0
0 1 0 -3 0 0 0 -1 3 0 2 -1 0 1 -1 0
3 2 -1 0 -1 1 0 -1 3 0 2 3 1 1 -1 0
5 2 3 3 1 4 3 -1 0 2 2 4 3 1 3 -1
2 2 3 4 1 2 3 2 1 3 0 3 4 2 3 0
-2 0 1 0 1 -1 0 3 -1 1 -1 -2 0 1 -1 2
CROSSREFS
Sequence in context: A116079 A153445 A376135 * A294196 A275794 A037746
KEYWORD
nonn
AUTHOR
R. H. Hardin, Mar 03 2012
STATUS
approved