A263625 Number of Seidel matrices of order 2n for which Cameron's first cohomology invariant is nonzero.

0, 0, 2, 21, 392, 15274

Offset

1,3

Links

Table of n, a(n) for n=1..6.

G. Greaves, J. H. Koolen, A. Munemasa, and F. Szöllősi, Equiangular lines in Euclidean spaces, arXiv:1403.2155 [math.CO], 2014-2015.

G. Greaves, J. H. Koolen, A. Munemasa, and F. Szöllősi, Equiangular lines in Euclidean spaces, Journal of Combinatorial Theory, Series A, 138 (2016), 208-235.

Crossrefs

Sequence in context: A098344 A228384 A216281 * A245686 A091315 A359716

Adjacent sequences: A263622 A263623 A263624 * A263626 A263627 A263628

Keyword

nonn,more

Author

N. J. A. Sloane, Oct 24 2015

Status

approved