A054938 Number of chiral chord diagrams on n nodes.

0, 0, 0, 1, 26, 348, 4466, 61726, 949795, 16331482, 312298796, 6587217199, 152030203190, 3811719561156, 103171205826822, 2998417379370294, 93127344062857976, 3078376281077418971, 107905190923235526392

Offset

1,5

Links

Table of n, a(n) for n=1..19.

V. A. Liskovets, Some easily derivable sequences, J. Integer Sequences, 3 (2000), #00.2.2.

Formula

a(n) = A054499(n)-A018191(n). [Liskovets, referring to offset 1 in A054499]. - R. J. Mathar, Oct 01 2011

Crossrefs

Sequence in context: A042306 A329300 A053494 * A161526 A161933 A162368

Adjacent sequences: A054935 A054936 A054937 * A054939 A054940 A054941

Keyword

nonn,easy

Author

N. J. A. Sloane, May 24 2000

Status

approved