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A219899 Number of classes of Butson-type Hadamard matrices of order 2n over 4th roots of unity. 1
1, 2, 1, 15, 10, 319, 752 (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. A219900.

Sequence in context: A083074 A181869 A141510 * A326600 A272304 A266521

Adjacent sequences:  A219896 A219897 A219898 * A219900 A219901 A219902

KEYWORD

nonn,more

AUTHOR

N. J. A. Sloane, Dec 12 2012

STATUS

approved

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Last modified September 21 23:10 EDT 2020. Contains 337274 sequences. (Running on oeis4.)