A208974 Number of 7-bead necklaces labeled with numbers -n..n allowing reversal, with sum zero and first and second differences in -n..n.

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

R. H. Hardin, Table of n, a(n) for n = 1..79

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: A098624 A116079 A153445 * A294196 A275794 A037746

Adjacent sequences: A208971 A208972 A208973 * A208975 A208976 A208977

Keyword

nonn

Author

R. H. Hardin, Mar 03 2012

Status

approved