A395573 a(n) is the permanent of the symmetric n X n matrix M defined by M(i,j) = min(i!,j!) for 1 <= i,j <= n.

1, 1, 3, 28, 976, 157056, 142447680, 865660372992, 40826781561544704, 16955839957555540131840, 69277788405128514469625856000, 3074181759368891298451197586833408000, 1620334845092184367116191438619804067430400000, 11009645929585373861063744613805873343760131162112000000

Offset

0,3

Links

Table of n, a(n) for n=0..13.

Example

a(3) = 28:
  [1, 1, 1]
  [1, 2, 2]
  [1, 2, 6]

Maple

a:= n-> `if`(n=0, 1, LinearAlgebra[Permanent](Matrix(n, (i, j)-> min(i!, j!)))):
seq(a(n), n=0..13);  # Alois P. Heinz, Apr 28 2026

Mathematica

a[0]:=1; a[n_]:=Permanent[Table[Min[i!, j!], {i, n}, {j, n}]]; Array[a, 14, 0]

Crossrefs

Cf. A000142, A004197, A152653 (determinant).

Sequence in context: A328791 A140990 A196735 * A208438 A122891 A390603

Adjacent sequences: A395570 A395571 A395572 * A395574 A395575 A395576

Keyword

nonn

Author

Stefano Spezia, Apr 28 2026

Status

approved