A374390 - OEIS

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

(list; graph; refs; listen; history; text; internal format)

OFFSET

0,3

LINKS

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. A374068 (minimal permanent).

KEYWORD

nonn,hard,more

AUTHOR

STATUS

approved