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 A088746 a(n) = determinant of upper left n X n matrix A_n of matrix A088745, where A_n has elements 1..n^2 with abs(det(A_n)) = max by adding elements on the lower and right border. 1
 1, -10, 205, -6300, 276363, -15615642, 861774366 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS Terms were computed by Hugo Pfoertner (see A088745 for program link). LINKS Table of n, a(n) for n=1..7. EXAMPLE The upper left 7x7 matrix of A088745 is: [ 1, 3, 8, 11, 24, 26, 48] [ 4, 2, 7, 16, 18, 36, 39] [ 6, 9, 5, 13, 22, 30, 40] [15, 12, 14, 10, 21, 34, 42] [17, 25, 23, 20, 19, 31, 47] [35, 27, 29, 33, 32, 28, 45] [37, 43, 46, 41, 49, 44, 38] MATHEMATICA (* first do *) Needs["LinearAlgebra`MatrixManipulation`"]; Needs["DiscreteMath`Combinatorica`"] (* then *) f[m_List] := Block[{k = 1, lmt, mxm = 0, mtx = m, mtxm, nbr = Sqrt@Length@Flatten@m, pm}, lmt = (2nbr + 1)!; pm = Reverse@ Range[nbr^2 + 1, (nbr + 1)^2]; While[k <= lmt, mtxr = AppendRows[mtx, Partition[Take[pm, nbr], 1]]; mtxc = AppendColumns[mtxr, {Take[pm, -(nbr + 1)]}]; ab = Det@mtxc; If[Abs@ab >= mxm, mxm = Abs@ab; mtxm = mtxc; Print[{ab, mtxc // MatrixForm}]]; k++; pm = NextPermutation@pm]; mtxm]; NestList[f, {{1}}, 6] (* Robert G. Wilson v *) CROSSREFS Cf. A088745. Sequence in context: A367200 A365177 A027014 * A293970 A356973 A356960 Adjacent sequences: A088743 A088744 A088745 * A088747 A088748 A088749 KEYWORD sign AUTHOR Paul D. Hanna, Oct 17 2003 EXTENSIONS Entries checked by Robert G. Wilson v, Sep 22 2006 STATUS approved

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Last modified December 8 08:36 EST 2023. Contains 367663 sequences. (Running on oeis4.)