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A328062 Lexicographically earliest permutation of [1,2,...,n] minimizing the positive value of the determinant of an n X n circulant matrix that uses this permutation as first row, written as triangle T(n,k), k <= n. 3
1, 2, 1, 1, 2, 3, 3, 1, 4, 2, 1, 2, 4, 5, 3, 1, 2, 4, 5, 6, 3, 1, 2, 4, 6, 7, 5, 3, 3, 1, 5, 4, 8, 6, 7, 2, 1, 2, 4, 6, 8, 9, 7, 5, 3, 5, 1, 7, 3, 8, 4, 10, 6, 9, 2, 1, 2, 3, 8, 6, 4, 9, 10, 11, 5, 7, 3, 1, 5, 4, 9, 8, 12, 10, 11, 6, 7, 2, 1, 2, 3, 5, 8, 7, 6, 9, 11, 12, 13, 10, 4 (list; table; graph; refs; listen; history; text; internal format)
OFFSET
1,2
LINKS
Hugo Pfoertner, Table of n, a(n) for n = 1..120, rows 1..15 of triangle, flattened
Wikipedia, Circulant matrix.
EXAMPLE
The triangle starts
1;
2, 1;
1, 2, 3;
3, 1, 4, 2;
1, 2, 4, 5, 3;
1, 2, 4, 5, 6, 3;
1, 2, 4, 6, 7, 5, 3;
3, 1, 5, 4, 8, 6, 7, 2;
1, 2, 4, 6, 8, 9, 7, 5, 3;
5, 1, 7, 3, 8, 4, 10, 6, 9, 2;
.
The 4th row of the triangle T(4,1)..T(4,4) = a(7)..a(10) is [3,1,4,2] because this is the lexicographically earliest permutation of [1,2,3,4] producing a circulant 4 X 4 matrix with minimum positive determinant A309257(4) = 80.
[3, 1, 4, 2;
2, 3, 1, 4;
4, 2, 3, 1;
1, 4, 2, 3].
All lexicographically earlier permutations lead to the other possible determinants -160, -80, 0, 160 with [1,3,2,4], [1,4,3,2], [2,3,1,4], and [2,4,1,3] producing determinants = -80.
CROSSREFS
Sequence in context: A153734 A285554 A128495 * A326281 A343026 A113136
KEYWORD
nonn,tabl
AUTHOR
Hugo Pfoertner, Oct 03 2019
STATUS
approved

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Last modified August 18 19:26 EDT 2024. Contains 375273 sequences. (Running on oeis4.)