A390903 a(n) is the permanent of the n X n matrix M(n) whose generic entry M(i, j, n) is 2*n - (i + j) with 1 <= i,j <= n.

1, 0, 1, 24, 916, 53520, 4490340, 513717120, 76996938816, 14652924572160, 3453133797288000, 987402920720832000, 336850171797789492480, 135167796476657190005760, 63029900191369587142867200, 33800579737307557482147840000, 20656583446419838426893576192000, 14271904174220731017886938071040000

Offset

0,4

Comments

Except for n = 2, the matrix M(n) is singular.

Links

Table of n, a(n) for n=0..17.

Example

a(4) = 916:
  [6, 5, 4, 3]
  [5, 4, 3, 2]
  [4, 3, 2, 1]
  [3, 2, 1, 0]

Mathematica

a[n_]:=Permanent[Table[2n-(i+j), {i, n}, {j, n}]]; Join[{1}, Array[a, 17]]

Prog

(PARI) a(n) = matpermanent(matrix(n, n, i, j, 2*n - (i + j))); \\ Michel Marcus, Nov 23 2025

Crossrefs

Cf. A005843, A390884.

Sequence in context: A061236 A266997 A359644 * A001784 A172206 A220804

Adjacent sequences: A390900 A390901 A390902 * A390904 A390905 A390906

Keyword

nonn

Author

Stefano Spezia, Nov 23 2025

Status

approved