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A263625 Number of Seidel matrices of order 2n for which Cameron's first cohomology invariant is nonzero. 0
0, 0, 2, 21, 392, 15274 (list; graph; refs; listen; history; text; internal format)
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 A087546

Adjacent sequences:  A263622 A263623 A263624 * A263626 A263627 A263628

KEYWORD

nonn,more,changed

AUTHOR

N. J. A. Sloane, Oct 24 2015

STATUS

approved

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Last modified March 1 08:23 EST 2021. Contains 341732 sequences. (Running on oeis4.)