A263625 - OEIS

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A263625

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

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`

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