A005312 Maximal sum of inverse squares of the singular values of symmetric anti-Hadamard matrices of order n. (Formerly M2659)

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

Offset

1,2

References

N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Links

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

Noga Alon and Van H. Vu, Anti-Hadamard Matrices, Coin Weighing, Threshold Gates, and Indecomposable Hypergraphs, Journal of Combinatorial Theory, Series A, Volume 79, Issue 1, July 1997, Pages 133-160.

R. L. Graham and N. J. A. Sloane, Anti-Hadamard matrices, Linear Alg. Applic., 62 (1984), 113-137, Table 1.

Crossrefs

Cf. A005313.

Sequence in context: A323692 A360782 A351821 * A341576 A143817 A297210

Adjacent sequences: A005309 A005310 A005311 * A005313 A005314 A005315

Keyword

nonn,hard,more

Author

N. J. A. Sloane.

Extensions

Definition corrected by Stefano Spezia, Jan 30 2022

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

Status

approved