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 A034921 Number of different determinants of n X n persymmetric matrices with entries {-1,0,+1}. 4
 3, 4, 9, 23, 67, 192, 833, 2857, 13797, 53336, 302115, 1271704 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS A persymmetric (or Hankel) matrix has M[ i,j ] = M[ i-k,j+k ] for all i and j (matrix is constant along antidiagonals). LINKS Table of n, a(n) for n=1..12. EXAMPLE For n = 1 and 2 the possible values for the determinant are {-1, 0, 1} and {-2, -1, 0, 1}. MATHEMATICA M[row_] := With[{m=Length[row]}, Table[RotateLeft[row, n][[1 ;; (m+1)/2]], {n, 0, (m-1)/2}]]; a[n_] := Det[M[#]]& /@ Tuples[{-1, 0, 1}, 2n-1] // Union // Length; Table[an = a[n]; Print["a(", n, ") = ", an]; an, {n, 1, 6}] (* Jean-François Alcover, Sep 04 2017 *) CROSSREFS Cf. A034917, A034918, A034919, A034920. Sequence in context: A299123 A245455 A296265 * A038222 A038629 A354545 Adjacent sequences: A034918 A034919 A034920 * A034922 A034923 A034924 KEYWORD nonn,nice,more AUTHOR Fred Lunnon, Dec 11 1999 EXTENSIONS More terms from Sam Handler (sam_5_5_5_0(AT)yahoo.com), Aug 08 2006 a(10)-a(12) from Bert Dobbelaere, Jan 26 2019 STATUS approved

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Last modified April 12 07:22 EDT 2024. Contains 371623 sequences. (Running on oeis4.)