A352177 a(n) is the number of symmetric Toeplitz anti-Hadamard matrices of order n whose sum of the inverse squares of their singular values is maximal.
1, 2, 1, 2, 1, 3, 1, 1, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1
Offset: 1
Links
- R. L. Graham and N. J. A. Sloane, Anti-Hadamard matrices, Linear Alg. Applic., 62 (1984), 113-137.
Formula
Conjectures: (Start)
a(n) = 1 for n > 9.
G.f.: x*(x + x^3 + 2*x^5 + x^8 + 1/(1 - x)). (End)
Comments