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%I #19 Jan 26 2019 04:26:03
%S 3,4,9,23,67,192,833,2857,13797,53336,302115,1271704
%N Number of different determinants of n X n persymmetric matrices with entries {-1,0,+1}.
%C A persymmetric (or Hankel) matrix has M[ i,j ] = M[ i-k,j+k ] for all i and j (matrix is constant along antidiagonals).
%e For n = 1 and 2 the possible values for the determinant are {-1, 0, 1} and {-2, -1, 0, 1}.
%t M[row_] := With[{m=Length[row]}, Table[RotateLeft[row, n][[1 ;; (m+1)/2]], {n, 0, (m-1)/2}]];
%t a[n_] := Det[M[#]]& /@ Tuples[{-1, 0, 1}, 2n-1] // Union // Length;
%t Table[an = a[n]; Print["a(", n, ") = ", an]; an, {n, 1, 6}] (* _Jean-François Alcover_, Sep 04 2017 *)
%Y Cf. A034917, A034918, A034919, A034920.
%K nonn,nice,more
%O 1,1
%A _Fred Lunnon_, Dec 11 1999
%E More terms from Sam Handler (sam_5_5_5_0(AT)yahoo.com), Aug 08 2006
%E a(10)-a(12) from _Bert Dobbelaere_, Jan 26 2019
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