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URL: https://oeis.org/A374283

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A374283
a(n) is the maximal permanent of an n X n symmetric Toeplitz matrix having 0 on the main diagonal and all the integers 1, 2, ..., n-1 off-diagonal.
4
1, 0, 1, 8, 256, 9978, 600052, 49036950, 5286564352, 725724599636
OFFSET
0,4
EXAMPLE
a(5) = 9978:
[0, 4, 3, 2, 1]
[4, 0, 4, 3, 2]
[3, 4, 0, 4, 3]
[2, 3, 4, 0, 4]
[1, 2, 3, 4, 0]
MATHEMATICA
a[0]=1; a[n_]:=Max[Table[Permanent[ToeplitzMatrix[Join[{0}, Part[Permutations[Range[n - 1]], i]]]], {i, (n-1)!}]]; Array[a, 11, 0]
CROSSREFS
Cf. A085807 (minimal), A358327.
Sequence in context: A128787 A013824 A010044 * A024290 A253165 A140338
KEYWORD
nonn,hard,more
AUTHOR
Stefano Spezia, Jul 02 2024
STATUS
approved