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 1-6 of 6 results.

A350566 a(n) is the maximum permanent of an n X n matrix using the integers 1 to n^2.

Original entry on oeis.org

1, 1, 14, 947, 161388, 56558003, 36757837732
Offset: 0

Views

Author

Hugo Pfoertner at the suggestion of Stefano Spezia, Jan 21 2022

Keywords

Comments

a(7) >= 38677620556961 corresponding to the matrix
14, 25, 39, 3, 45, 2, 42
32, 21, 10, 46, 5, 47, 8
31, 20, 9, 48, 1, 49, 6
44, 24, 18, 33, 13, 34, 15
22, 29, 35, 12, 36, 11, 37
16, 26, 38, 7, 43, 4, 40
23, 41, 30, 19, 27, 17, 28 . - Robert Israel, Mar 19 2025
a(7) >= 38677691168324 corresponding to the matrix
1, 4, 14, 25, 39, 42, 45
5, 6, 16, 26, 38, 40, 43
11, 12, 22, 29, 35, 36, 37
17, 19, 23, 41, 30, 28, 27
33, 34, 44, 24, 18, 15, 13
48, 46, 32, 21, 10, 8, 3
49, 47, 31, 20, 9, 7, 2. - Pontus von Brömssen, Mar 20 2025

Examples

			a(2) = 14:
  [2, 3;
   4, 1]
.
a(3) = 947:
  [3, 7, 6;
   9, 4, 1;
   2, 5, 8]
.
a(4) = 161388:
  [ 2,  3, 16,  6;
   11, 13,  4, 10;
    8,  9,  5, 15;
   14, 12,  1,  7]
.
a(5) = 56558003:
  [10,  2, 19, 25,  3;
   11,  5, 23, 20,  8;
   21, 14, 12,  9, 15;
   13, 24,  6,  1, 18;
   16, 17,  7,  4, 22]
.
a(6) = 36757837732:
  [32, 30,  3, 19, 23,  2;
    1,  5, 34, 14, 11, 36;
   17, 18, 15, 31, 22, 16;
   29, 28,  7, 20, 24,  6;
   26, 25, 10, 21, 27,  9;
    4,  8, 35, 13, 12, 33]
		

Crossrefs

Cf. A085000 (determinant), A350565 (minimum), A350858, A350859, A358487 (elements 0 to n^2-1).

Programs

  • Python
    from itertools import permutations
    from sympy import Matrix
    def A350566(n): return 1 if n == 0 else max(Matrix(n,n,p).per() for p in permutations(range(1,n**2+1))) # Chai Wah Wu, Jan 21 2022

A350858 Minimal permanent of an n X n matrix whose elements are a permutation of the first n^2 prime numbers.

Original entry on oeis.org

1, 2, 29, 3664, 1820642, 2276752048, 5697057180536
Offset: 0

Views

Author

Stefano Spezia, Jan 19 2022

Keywords

Examples

			a(2) = 29:
    2    3
    5    7
a(3) = 3664:
    2    3    5
    7   13   19
   11   17   23
		

Crossrefs

Cf. A114533, A180128, A350565, A350859 (maximal).

Programs

  • Python
    from itertools import permutations
    from sympy import Matrix
    def A350858(n): return 1 if n == 0 else min(Matrix(n,n,p).per() for p in permutations(prime(m) for m in range(1,n**2+1))) # Chai Wah Wu, Jan 21 2022

Extensions

a(4)-a(6) from Hugo Pfoertner, Jan 21 2022

A358486 a(n) is the minimal permanent of an n X n matrix using the integers 0 to n^2 - 1.

Original entry on oeis.org

1, 0, 2, 128, 18948, 40179728, 2863042492
Offset: 0

Views

Author

Stefano Spezia, Nov 18 2022

Keywords

Examples

			a(3) = 128:
     [0, 1, 2;
      4, 6, 8;
      3, 5, 7]
		

Crossrefs

Cf. A350565 (integers 1 to n^2), A358487 (maximal).

Extensions

a(4)-a(6) from Hugo Pfoertner, Nov 19 2022

A351610 Minimal permanent of an n X n symmetric matrix using the integers 1 to n*(n + 1)/2.

Original entry on oeis.org

1, 1, 7, 163, 9850, 1243806, 284995981
Offset: 0

Views

Author

Stefano Spezia, Feb 14 2022

Keywords

Examples

			a(3) = 163:
   1    2    3
   2    5    4
   3    4    6
a(4) = 9850:
   1    2    3    4
   2    8    5    6
   3    5    9    7
   4    6    7   10
		

Crossrefs

Extensions

a(5)-a(6) from Hugo Pfoertner, Feb 15 2022

A364203 Triangle read by rows: T(n, k) is the number of n X n matrices of rank k using all the integers from 1 to n^2.

Original entry on oeis.org

1, 0, 24, 0, 2736, 360144
Offset: 1

Views

Author

Stefano Spezia, Jul 13 2023

Keywords

Examples

			The triangle begins:
  1;
  0,   24;
  0, 2736, 360144;
  ...
		

Crossrefs

Cf. A085000 (maximal determinant), A088020 (row sums), A350565 (minimal permanent), A350566 (maximal permanent), A364206 (right diagonal).
Cf. A364226 (with prime numbers).

A364206 a(n) is the number of n X n nonsingular matrices using all the integers from 1 to n^2.

Original entry on oeis.org

1, 24, 360144, 20914499571840
Offset: 1

Views

Author

Stefano Spezia, Jul 13 2023

Keywords

Crossrefs

Right diagonal of A364203.
Cf. A085000 (maximal determinant), A350565 (minimal permanent), A350566 (maximal permanent).
Cf. A364227 (with prime numbers).

Formula

a(n) = (n^2)! - A221976(n). - Vaclav Kotesovec, Jul 16 2023

Extensions

a(4) from Vaclav Kotesovec, Jul 16 2023 (using A221976)
Showing 1-6 of 6 results.