The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A005312 (Bold, blue-underlined text is an addition; faded, red-underlined text is a ~~deletion~~.)
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A005312

Maximal sum of inverse squares of the singular values of symmetric anti-Hadamard matrices of order n.
(history; published version)

#23 by N. J. A. Sloane at Sun Feb 20 22:46:04 EST 2022

STATUS

editing

approved

#22 by Stefano Spezia at Sun Feb 20 11:44:50 EST 2022

DATA

1, 3, 7, 16, 46, 138, 624

KEYWORD

nonn,hard,more

EXTENSIONS

a(7) confirmed and inserted by Stefano Spezia, Feb 20 2022

STATUS

approved

editing

#21 by N. J. A. Sloane at Sun Jan 30 13:05:40 EST 2022

STATUS

editing

approved

#20 by N. J. A. Sloane at Sun Jan 30 13:05:38 EST 2022

LINKS

R. L. Graham and N. J. A. Sloane, <a href="http://dx.doi.org/10.1016/0024-3795(84)90090-9">Anti-Hadamard matrices</a>, Linear Alg. Applic., 62 (1984), 113-137, Table 1.

#19 by Stefano Spezia at Sun Jan 30 12:51:06 EST 2022

NAME

Number Maximal sum of inverse squares of the singular values of symmetric anti-Hadamard matrices of order n.

CROSSREFS

Cf. A005313.

EXTENSIONS

Definition corrected by Stefano Spezia, Jan 30 2022

STATUS

approved

editing

#18 by N. J. A. Sloane at Fri Jan 28 13:33:01 EST 2022

STATUS

editing

approved

#17 by N. J. A. Sloane at Fri Jan 28 13:32:59 EST 2022

LINKS

Noga Alon and Van H. Vu, <a href="https://doi.org/10.1006/jcta.1997.2780">Anti-Hadamard Matrices, Coin Weighing, Threshold Gates, and Indecomposable Hypergraphs</a>, Journal of Combinatorial Theory, Series A, Volume 79, Issue 1, July 1997, Pages 133-160.

STATUS

approved

editing

#16 by N. J. A. Sloane at Fri Jan 28 10:49:55 EST 2022

STATUS

editing

approved

#15 by N. J. A. Sloane at Fri Jan 28 10:49:53 EST 2022

KEYWORD

nonn,more

STATUS

approved

editing

#14 by N. J. A. Sloane at Sat May 07 00:22:04 EDT 2016

STATUS

proposed

approved