13×13 {-1, +1} matrix of maximal determinant

|Det R| = 3645×212 = 15×35×212

Ratio of |Det R| to Barba bound: 1

M=RTR=R RT:

13  1  1  1  1  1  1  1  1  1  1  1  1
 1 13  1  1  1  1  1  1  1  1  1  1  1
 1  1 13  1  1  1  1  1  1  1  1  1  1
 1  1  1 13  1  1  1  1  1  1  1  1  1
 1  1  1  1 13  1  1  1  1  1  1  1  1
 1  1  1  1  1 13  1  1  1  1  1  1  1
 1  1  1  1  1  1 13  1  1  1  1  1  1
 1  1  1  1  1  1  1 13  1  1  1  1  1
 1  1  1  1  1  1  1  1 13  1  1  1  1
 1  1  1  1  1  1  1  1  1 13  1  1  1
 1  1  1  1  1  1  1  1  1  1 13  1  1
 1  1  1  1  1  1  1  1  1  1  1 13  1
 1  1  1  1  1  1  1  1  1  1  1  1 13

R:

+++++-+++--+-
-+++++-+++--+
+-+++++-+++--
-+-+++++-+++-
--+-+++++-+++
+--+-+++++-++
++--+-+++++-+
+++--+-+++++-
-+++--+-+++++
+-+++--+-++++
++-+++--+-+++
+++-+++--+-++
++++-+++--+-+

Notes:

  1. Found by Raghavarao [R].
  2. Circulant.
  3. R unique up to equivalence [CD].

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Page created 26 January 2002.
Last modified 5 December 2003.
Comments: maxdet@indiana.edu