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A158865 Smallest maximal excess attained by an equivalence class of Hadamard matrices of order 4n. 0

%I

%S 0,8,20,36,56,80,108,140

%N Smallest maximal excess attained by an equivalence class of Hadamard matrices of order 4n.

%C The excess of a {-1,1} matrix is the sum of its elements. The maximal excess of an equivalence class of Hadamard matrices (cf. A007299) is the largest excess attained by a member of the class. The largest maximal excess of any equivalence class is given by A004118.

%D Best, M. R. The excess of a Hadamard matrix. Nederl. Akad. Wetensch. Proc. Ser. A {80}=Indag. Math. 39 (1977), no. 5, 357-361.

%D Brown, Thomas A. and Spencer, Joel H., Minimization of +-1 matrices under line shifts. Colloq. Math. 23 (1971), 165-171, 177 (errata).

%D R. Craigen and H. Kharaghani, Weaving Hadamard matrices with maximum excess and classes with small excess. J. Combinatorial Designs 12 (2004), 233-255.

%F For bounds on a(n), see A004118.

%e All equivalence classes in orders 20 and 28 attain the same maximal excess. In order 16, three classes attain maximal excess 64 and two attain maximal excess 56. In order 24, 56 equivalence classes attain maximal excess 112 and four attain maximal excess 108.

%K hard,more,nonn

%O 0,2

%A _William P. Orrick_, Mar 28 2009

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Last modified June 23 12:05 EDT 2021. Contains 345401 sequences. (Running on oeis4.)