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A219900 Number of ACT classes of Butson-type Hadamard matrices of order 2n over 4th roots of unity. 1
1, 2, 1, 10, 7, 167, 298 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..7.

P. H. J. Lampio and F. Szollosi, Quaternary complex Hadamard matrices.

P. H. J. Lampio, F. Szollosi and Patric R. J. Östergård, The quaternary complex Hadamard matrices of orders 10, 12, and 14, Discrete Math., 313 (2012), 189-206.

CROSSREFS

Cf. A219899.

Sequence in context: A081099 A213252 A122017 * A136233 A113088 A060694

Adjacent sequences:  A219897 A219898 A219899 * A219901 A219902 A219903

KEYWORD

nonn,more

AUTHOR

N. J. A. Sloane, Dec 12 2012

STATUS

approved

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Last modified September 24 03:38 EDT 2020. Contains 337316 sequences. (Running on oeis4.)