This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A215645 #24 Apr 11 2013 16:38:17
%S A215645 1,1,1,1,1,1,1,4,1,2,3,5,6,7,8,8,1,7,10,10,10
%N A215645 Depth for {+1,-1} maximal determinant matrices: minimal depth for which a proper submatrix is also a maximal determinant matrix.
%C A215645 The complementary depth m(A) of a maximal determinant {+1,-1} matrix of order n is the maximum m < n such that a maximal determinant matrix of order m occurs as a proper submatrix of A, or 0 if n = 1. The depth d(A) of A is d(A) := n - m(A). The depth d(n) is the minimum of d(A) over all maximal determinant matrices A of order n.
%C A215645 We calculated the first 21 terms of the sequence by an exhaustive computation of minors of known maximal determinant matrices as of August 2012.
%H A215645 R. P. Brent, <a href="http://wwwmaths.anu.edu.au/~brent/maxdet/">The Hadamard Maximal Determinant Problem</a>
%H A215645 Richard P. Brent and Judy-anne H. Osborn, <a href="http://arxiv.org/abs/1208.3819">On minors of maximal determinant matrices</a>, arXiv:1208.3819, 2012.
%e A215645 For n = 11 the depth is 3 because there is a maximal determinant matrix of order 11 that has a maximal determinant submatrix of order 8 = 11-3, but no larger proper maximal determinant submatrices. Note that only one of the three Hadamard equivalence classes of maximal determinant matrices of order 11 gives depth 3; the others give depth 4, but we take the minimum.
%Y A215645 Cf. A003432, A003433, A215644.
%K A215645 nonn,hard,more
%O A215645 1,8
%A A215645 _Richard P. Brent_ and _Judy-anne Osborn_, Aug 18 2012