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This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A089479 Triangle T(n,k) read by rows, where T(n,k) = number of times the permanent of a real n X n (0,1)-matrix takes the value k, for n >= 0, 0 <= k <= n!.

Original entry on oeis.org

0, 1, 1, 1, 9, 6, 1, 265, 150, 69, 18, 9, 0, 1, 27713, 13032, 10800, 4992, 4254, 1440, 1536, 576, 648, 24, 288, 96, 48, 0, 72, 0, 0, 0, 16, 0, 0, 0, 0, 0, 1, 10363361, 3513720, 4339440, 2626800, 3015450, 1451400, 1872800, 962400, 1295700, 425400, 873000
Offset: 0

Views

Author

Hugo Pfoertner, Nov 05 2003

Keywords

Comments

The last element of each row is 1, corresponding to the n X n "all 1" matrix with permanent = n!. The first 4 rows were provided by Wouter Meeussen. The 6th row was computed by Gordon F. Royle: 13906734081, 2722682160, 4513642920, 3177532800, 4466769300, 2396826720, 3710999520, 2065521600, 3253760550, 1468314000, 2641593600, 1350475200, 2210277600, 1034061120,... .

Examples

			Triangle begins:
    0,     1;
    1,     1;
    9,     6,     1;
  265,   150,    69,   18,    9,    0,    1;
27713, 13032, 10800, 4992, 4254, 1440, 1536, 576, 648, 24, 288,
                   96, 48, 0, 72, 0, 0, 0, 16, 0, 0, 0, 0, 0, 1;
  ...
		

Crossrefs

T(n,0) = A088672(n), T(n,1) = A089482(n). The n-th row of the table contains A087983(n) nonzero entries. For n>2 A089477(n) gives the position of the first zero entry in the n-th row.
Cf. A089480 (occurrence counts for permanents of non-singular (0,1)-matrices), A089481 (occurrence counts for permanents of singular (0,1)-matrices).
Cf. A000290, A038507 (row lengths), A002416 (row sums).

Formula

From Geoffrey Critzer, Dec 20 2023: (Start)
Sum_{k=1..n!} T(n,k) = A227414(n).
For n>2, T(n,n!-(n-1)!) = n^2, the number of matrices with exactly one 0 entry. (End)

Extensions

Edited by Alois P. Heinz, Dec 20 2023