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 1-10 of 12 results. Next

A087983 Number of different values taken by permanent of n X n (0,1)-matrix.

Original entry on oeis.org

1, 2, 3, 6, 16, 51, 220, 1179, 7980
Offset: 0

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Author

Wouter Meeussen, Oct 29 2003

Keywords

Examples

			For a 4 X 4 matrix the 16 possible permanents and their multiplicieties are:
{{0, 27713}, {1, 13032}, {2, 10800}, {3, 4992}, {4, 4254}, {5, 1440}, {6, 1536}, {7, 576}, {8, 648}, {9, 24}, {10, 288}, {11, 96}, {12, 48}, {14, 72}, {18, 16}, {24, 1}}
		

Crossrefs

Extensions

a(6)=220 from Gordon F. Royle, Nov 05 2003
a(7) from Giovanni Resta, Mar 29 2006
a(0)=1 prepended by Alois P. Heinz, Apr 28 2020
a(8) from Minfeng Wang, Oct 04 2024

A013588 Smallest positive integer not the determinant of an n X n {0,1}-matrix.

Original entry on oeis.org

2, 2, 3, 4, 6, 10, 19, 41, 103, 269
Offset: 1

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Author

Gerhard R. Paseman (paseman(AT)prado.com)

Keywords

Comments

This majorizes the sequence of maximal determinants only up to the 6th term. It is conjectured that the sequence of maximal determinants majorizes this for all later terms.
The first term needing verification is a(11) >= 739. a(12) = 2173 has been verified by Brent, Orrick, Osborn, and Zimmermann in 2010. Lower bounds for the next terms: a(13) >= 6739, a(14) >= 21278, a(15) >= 69259, a(16) >= 230309. - Hugo Pfoertner, Jan 03 2020
Asymptotically, the sequence is at least exponential as there is an exponential lower bound of a(n) >= 2^n / (201*n) due to Shah 2022. - Rikhav Shah, Jul 09 2025

Examples

			There is no 3 X 3 {0,1}-matrix with determinant 3, as such a matrix must have a row with at least one 0 in it.
		

Crossrefs

Programs

  • Python
    from itertools import product
    from sympy import Matrix
    def A013588(n):
        s, k = set(Matrix(n,n,p).det() for p in product([0,1],repeat=n**2)), 1
        while k in s:
            k += 1
        return k # Chai Wah Wu, Oct 01 2021

Extensions

Extended by William P. Orrick, Jan 12 2006. a(7), a(8) and a(9) computed by Miodrag Zivkovic. a(7) and a(8) independently confirmed by Antonis Charalambides. a(10) computed by William Orrick.

A118985 Number of different values taken by the determinant of a symmetric real (0,1)-matrix of order n.

Original entry on oeis.org

1, 2, 3, 5, 7, 11, 19, 40, 91, 214, 577
Offset: 0

Views

Author

Giovanni Resta, May 08 2006

Keywords

Crossrefs

Cf. A006125 (number of symmetric real (0,1)-matrices of order (n-1)).

Extensions

a(0)=1 prepended by Alois P. Heinz, Mar 16 2019
a(8) from Minfeng Wang, Jun 11 2024
a(9) from Minfeng Wang, Jun 12 2024
a(10) from Hugo Pfoertner, Jun 25 2024

A089478 Triangle T(n,k) read by rows, where T(n,k) = number of times the determinant of a real n X n (0,1)-matrix takes the value k, for n >= 0, 0 <= k <= A003432(n).

Original entry on oeis.org

0, 1, 1, 1, 10, 3, 338, 84, 3, 42976, 10020, 1200, 60, 21040112, 4851360, 1213920, 144720, 43560, 3600, 39882864736, 9240051240, 3868663680, 768723480, 418703040, 63612360, 46569600, 6438600, 5014800, 529200, 292604283435872
Offset: 0

Views

Author

Hugo Pfoertner, Nov 04 2003

Keywords

Comments

The first 4 rows were provided by Wouter Meeussen.

Examples

			a(4) = T(2,1) = 3 because there are 3 different (0,1)-matrices with determinant=1:
  ((1,0),(0,1)), ((1,1),(0,1)), ((1,0),(1,1)).
Triangle T(n,k) begins:
         0,       1;
         1,       1;
        10,       3;
       338,      84,       3;
     42976,   10020,    1200,     60;
  21040112, 4851360, 1213920, 144720, 43560, 3600;
  ...
		

Crossrefs

Cf. T(n,0) = A046747(n), T(n,1) = A086264(n), T(n,A003432(n)) = A051752(n).
The n-th row of the table contains A089472(n) nonzero entries.
Cf. A089479.

Programs

Extensions

Edited by Alois P. Heinz, Dec 20 2023

A118987 Number of different values taken by the determinant of a symmetric real (+1,-1)-matrix of order n.

Original entry on oeis.org

1, 2, 2, 3, 5, 7, 11, 19, 40, 91, 214
Offset: 0

Views

Author

Giovanni Resta, May 08 2006

Keywords

Crossrefs

Cf. A006125 (number of symmetric real (+1,-1)-matrices of order (n-1)).

Extensions

a(0)=1 prepended by Alois P. Heinz, Mar 16 2019
a(8) from Minfeng Wang, Jun 10 2024
a(9)-a(10) from Minfeng Wang, Jun 12 2024

A099834 Maximum number of different determinants that can be produced by permuting the elements of a 3 X 3 integer matrix with nonnegative entries <= n.

Original entry on oeis.org

5, 15, 53, 109, 209, 351, 573, 811, 1193, 1509, 1971, 2501, 3183, 3769, 4511, 5025, 5641, 6165, 6600, 6964, 7354, 7696, 7960, 8110, 8404, 8606, 8704, 8846, 8962, 9125, 9210, 9284, 9362, 9420
Offset: 1

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Author

Hugo Pfoertner, Oct 29 2004

Keywords

Comments

For large values of n it is always possible to find a matrix that produces A088021(3)=10080 different determinants. Examples are given in the link. Currently (October 2004) the smallest known n for which a(n)=10080 is 100. The elements of the corresponding matrix are given in A098072.

Examples

			a(10)=1509: A corresponding set of matrix elements is {10,9,9,8,7,5,2,1,0}.
		

Crossrefs

Cf. A099815 largest determinant that can be produced by the optimal set of matrix elements.

A108150 Number of different nonnegative values taken by the determinant of a real (0,1)-matrix of order n.

Original entry on oeis.org

1, 2, 2, 3, 4, 6, 10, 22, 46, 114, 294
Offset: 0

Views

Author

William P. Orrick, Jan 12 2006

Keywords

References

  • For references and links see A089472.

Crossrefs

A089472 is the main entry for this sequence. Cf. A003432, A013588, A051236.

Formula

a(1)=2, a(n) = (A089472(n) + 1) / 2 for n>1

Extensions

a(0)=1 prepended by Alois P. Heinz, Mar 17 2019

A373915 Determinants of symmetric real {0,1}-matrices of order 9 that only occur as positive values.

Original entry on oeis.org

89, 94, 95, 97, 98, 99, 101, 102, 105, 110, 116, 125, 144
Offset: 1

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Author

Hugo Pfoertner, Jun 23 2024

Keywords

Comments

The non-occurrence of the corresponding negative determinants causes the difference A089472(9) - A118985(9) = 227 - 214 = 13.
A similar situation already occurs for 7 X 7 matrices, where the 3 determinant values -20, -24, -32 only occur with negative signs.

Crossrefs

A306837 Number of unimodular n X n matrices with elements {0, 1}.

Original entry on oeis.org

1, 6, 168, 20040, 9702720, 18480102480, 135491563468800, 3766962568171582080
Offset: 1

Views

Author

Steven E. Thornton, Mar 12 2019

Keywords

Comments

An integer matrix is unimodular if its determinant is -1 or +1.

Crossrefs

Number of different values taken by the determinant is in A089472.
Maximum determinant is in A003432.
A363862 gives equivalence classes up to row and column permutation.

Extensions

a(7) and a(8) from Brendan McKay, Jun 25 2023

A373916 Numbers that are the determinant of real {0,1}-matrices of order 10, but not of symmetric such matrices.

Original entry on oeis.org

253, 268, 274, 294, 304
Offset: 1

Views

Author

Hugo Pfoertner, Jun 25 2024

Keywords

Comments

This property also applies to the corresponding negative values.

Crossrefs

Showing 1-10 of 12 results. Next