A098852 Number of triangle-free self-dual configurations of type (n_3).

0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1, 2, 6, 40, 307

Offset

1,18

Links

Table of n, a(n) for n=1..21.

A. Betten, G. Brinkmann and T. Pisanski, Counting symmetric configurations v_3, Discrete Appl. Math., 99 (2000), 331-338.

Crossrefs

Cf. A001403, A100001, A023994.

Sequence in context: A351739 A098854 A056787 * A274482 A274277 A120592

Adjacent sequences: A098849 A098850 A098851 * A098853 A098854 A098855

Keyword

nonn,hard,more

Author

N. J. A. Sloane, Nov 05 2004

Status

approved