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.

A089472 Number of different values taken by the determinant of a real (0,1)-matrix of order n.

Original entry on oeis.org

1, 2, 3, 5, 7, 11, 19, 43, 91, 227, 587
Offset: 0

Views

Author

Hugo Pfoertner, Nov 04 2003

Keywords

Comments

Lower bounds: a(11) >= 1623, a(12) >= 4605, a(13) >= 14365, a(14) >= 44535, a(15) >= 145273, a(16) >= 476947

Examples

			a(7)=43 because a 7X7 (0,1)-matrix A_7 can produce the values abs(det(A_7))= {0,1,...,17,18,20,24,32}
		

Crossrefs

Cf. A003432 (largest determinant of (0, 1)-matrix), A013588 (smallest integer not representable as determinant of (0, 1)-matrix), A089478 (occurrence counts), A087983 (number of different values taken by permanent of (0, 1)-matrix).

Extensions

a(1)..a(4) from Wouter Meeussen.
a(7) verified by Gordon F. Royle.
Extended by William Orrick, Jan 12 2006. a(8) and a(9) computed by Miodrag Zivkovic. a(8) independently confirmed by Antonis Charalambides. a(10) computed by William Orrick.
Edited by Max Alekseyev, May 02 2011
a(0)=1 prepended by Alois P. Heinz, Mar 16 2019

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

A051752 Number of n X n (real) {0,1}-matrices having determinant A003432(n).

Original entry on oeis.org

1, 1, 3, 3, 60, 3600, 529200, 75600, 195955200, 13716864000
Offset: 0

Views

Author

Keywords

Crossrefs

Extensions

a(5) = 3600 from Daniel P. Corson (danl(AT)MIT.EDU), Jan 09 2000
a(6) = 529200, a(7) = 75600 from Ulrich Hermisson (uhermiss(AT)rz.uni-leipzig.de), Feb 25 2003
More terms from Miodrag Zivkovic (ezivkovm(AT)matf.bg.ac.yu), Feb 28 2006
a(0)=1 prepended by Alois P. Heinz, Dec 20 2023
Showing 1-3 of 3 results.