A374390 a(n) is the maximal permanent of an n X n symmetric Toeplitz matrix having 0 on the main diagonal and all the first n-1 primes off-diagonal.

1, 0, 4, 36, 1936, 144260, 31972988, 6800311204, 2560967581304, 975834087080060, 557171087172087364

Offset

0,3

Links

Table of n, a(n) for n=0..10.

Wikipedia, Toeplitz Matrix.

Example

a(5) = 144260:
  [0, 7, 5, 3, 2]
  [7, 0, 7, 5, 3]
  [5, 7, 0, 7, 5]
  [3, 5, 7, 0, 7]
  [2, 3, 5, 7, 0]

Mathematica

a[n_]:=Max[Table[Permanent[ToeplitzMatrix[Join[{0}, Part[Permutations[Prime[Range[n-1]]], i]]]], {i, (n-1)!}]]; Join[{1}, Array[a, 10]]

Crossrefs

Cf. A374345.

Cf. A374386, A374387, A374388, A374389.

Cf. A374068 (minimal permanent).

Sequence in context: A152287 A086857 A174864 * A175493 A179870 A001152

Adjacent sequences: A374387 A374388 A374389 * A374391 A374392 A374393

Keyword

nonn,hard,more

Author

Stefano Spezia, Jul 07 2024

Status

approved