cp's OEIS Frontend

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.

Showing 1-3 of 3 results.

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

A089480 Triangle T(n,k) read by rows, where T(n,k) = number of times the permanent of a real nonsingular n X n (0,1)-matrix takes the value k, for n >= 1, 1 <= k <= A000255(n).

Original entry on oeis.org

1, 6, 150, 6, 18, 13032, 1440, 4992, 672, 1440, 288, 576, 0, 24, 0, 96, 3513720, 693840, 2626800, 604200, 1451400, 468000, 962400, 252000, 425400, 190800, 379200, 97200, 205440, 100800, 132000, 28800, 108000, 28800, 44400, 33600, 61200, 9600, 14400, 0
Offset: 1

Views

Author

Hugo Pfoertner, Nov 04 2003

Keywords

Comments

This sequence was first provided by Jaap Spies.

Crossrefs

T(n, A000255(n)) = A052655(n). The n-th row of the table contains A089475(n) nonzero entries. Cf. A089479 occurrence counts for permanents of all (0, 1)-matrices, A089481 occurrence counts for permanents of singular (0, 1)-matrices.

A089476 Number of different values taken by the permanent of a real singular (0,1)-matrix of order n.

Original entry on oeis.org

1, 2, 4, 10, 32, 136
Offset: 1

Views

Author

Hugo Pfoertner, Nov 11 2003

Keywords

Examples

			a(4)=10 because the permanents of singular (0, 1)-matrices can take the values 0, 2, 4, 6, 8, 10, 12, 14, 18, 24.
		

Crossrefs

A089475 gives different permanents of nonsingular (0, 1)-matrices, A089481 occurrence counts for permanents of singular (0, 1)-matrices, A087983 different permanents of all (0, 1)-matrices.

Extensions

a(6) from Jaap Spies, Nov 28 2003
Showing 1-3 of 3 results.