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.

A374341 a(n) is the maximal determinant of an n X n symmetric Toeplitz matrix having 1 on the main diagonal and all the first n-1 primes off-diagonal.

Original entry on oeis.org

1, 1, -3, 15, 259, 1608, 1582152, 157042600, 11778545664, 3336975844504, 440384712302421
Offset: 0

Views

Author

Stefano Spezia, Jul 05 2024

Keywords

Examples

			a(5) = 1608:
  [1, 7, 2, 3, 5]
  [7, 1, 7, 2, 3]
  [2, 7, 1, 7, 2]
  [3, 2, 7, 1, 7]
  [5, 3, 2, 7, 1]
		

Crossrefs

Cf. A374340 (minimal), A374342 (maximal absolute value), A374343 (minimal nonzero absolute value), A374067 (minimal permanent), A374345 (maximal permanent).

Programs

  • Mathematica
    a[n_]:=Max[Table[Det[ToeplitzMatrix[Join[{1},Part[Permutations[Prime[Range[n-1]]],i]]]],{i,(n-1)!}]]; Join[{1},Array[a,10]]

A374342 a(n) is the maximal absolute value of the determinant of an n X n symmetric Toeplitz matrix having 1 on the main diagonal and all the first n-1 primes off-diagonal.

Original entry on oeis.org

1, 1, 3, 15, 259, 12167, 1708047, 157042600, 33081320935, 3336975844504, 579469550006151
Offset: 0

Views

Author

Stefano Spezia, Jul 05 2024

Keywords

Examples

			a(5) = 12167:
  [1, 2, 7, 3, 5]
  [2, 1, 2, 7, 3]
  [7, 2, 1, 2, 7]
  [3, 7, 2, 1, 2]
  [5, 3, 7, 2, 1]
		

Crossrefs

Cf. A374340 (minimal), A374341 (maximal), A374343 (minimal nonzero absolute value), A374067 (minimal permanent), A374345 (maximal permanent).

Programs

  • Mathematica
    a[n_]:=Max[Table[Abs[Det[ToeplitzMatrix[Join[{1},Part[Permutations[Prime[Range[n-1]]],i]]]]],{i,(n-1)!}]]; Join[{1},Array[a,10]]

Formula

a(n) = max(abs(A374340(n)),A374341(n)).

A374343 a(n) is the minimal absolute value of the determinant of a nonsingular n X n symmetric Toeplitz matrix having 1 on the main diagonal and all the first n-1 primes off-diagonal.

Original entry on oeis.org

1, 1, 3, 8, 7, 32, 81, 504, 327, 95
Offset: 0

Views

Author

Stefano Spezia, Jul 05 2024

Keywords

Examples

			a(5) = 32:
  [1, 3, 2, 5, 7]
  [3, 1, 3, 2, 5]
  [2, 3, 1, 3, 2]
  [5, 2, 3, 1, 3]
  [7, 5, 2, 3, 1]
		

Crossrefs

Cf. A374340 (minimal), A374341 (maximal), A374342 (maximal absolute value), A374067 (minimal permanent), A374345 (maximal permanent).

Programs

  • Mathematica
    a[n_]:=Min[Select[Table[Abs[Det[ToeplitzMatrix[Join[{1},Part[Permutations[Prime[Range[n-1]]],i]]]]],{i,(n-1)!}],Positive]]; Join[{1},Array[a,10]]

A374345 a(n) is the maximal permanent of an n X n symmetric Toeplitz matrix having 1 on the main diagonal and all the first n-1 primes off-diagonal.

Original entry on oeis.org

1, 1, 5, 59, 2454, 177998, 36960008, 7670953632, 2822399976144, 1061085324952592, 598646324654443008
Offset: 0

Views

Author

Stefano Spezia, Jul 05 2024

Keywords

Examples

			a(5) = 177998:
  [1, 7, 5, 3, 2]
  [7, 1, 7, 5, 3]
  [5, 7, 1, 7, 5]
  [3, 5, 7, 1, 7]
  [2, 3, 5, 7, 1]
		

Crossrefs

Programs

  • Mathematica
    a[n_]:=Max[Table[Permanent[ToeplitzMatrix[Join[{1},Part[Permutations[Prime[Range[n-1]]],i]]]],{i,(n-1)!}]]; Join[{1},Array[a,10]]

A374386 a(n) is the minimal determinant of an n X n symmetric Toeplitz matrix having 0 on the main diagonal and all the first n-1 primes off-diagonal.

Original entry on oeis.org

1, 0, -4, 24, -324, -15164, -1453072, -161765904, -37905894000, -1376219654680, -718058901423168, -163742479201610036
Offset: 0

Views

Author

Stefano Spezia, Jul 07 2024

Keywords

Examples

			a(5) = -15164:
  [0, 2, 7, 3, 5]
  [2, 0, 2, 7, 3]
  [7, 2, 0, 2, 7]
  [3, 7, 2, 0, 2]
  [5, 3, 7, 2, 0]
		

Crossrefs

Cf. A374387 (maximal), A374388 (maximal absolute value), A374389 (minimal nonzero absolute value).
Cf. A374068 (minimal permanent), A374390 (maximal permanent).

Programs

  • Mathematica
    a[n_]:=Min[Table[Det[ToeplitzMatrix[Join[{0},Part[Permutations[Prime[Range[n-1]]],i]]]],{i,(n-1)!}]]; Join[{1},Array[a,10]]

Extensions

a(11) from Giorgos Kalogeropoulos, Jul 10 2024

A374619 a(n) is the number of distinct values of the determinant of an n X n symmetric Toeplitz matrix having 1 on the main diagonal and all the first n-1 primes off-diagonal.

Original entry on oeis.org

1, 1, 1, 2, 6, 22, 120, 717, 5039, 40312, 362874
Offset: 0

Views

Author

Stefano Spezia, Jul 14 2024

Keywords

Crossrefs

Programs

  • Mathematica
    a[n_]:=CountDistinct[Table[Det[ToeplitzMatrix[Join[{1},Part[Permutations[Prime[Range[n-1]]], i]]]], {i, (n -1)!}]]; Join[{1}, Array[a, 10]]

Formula

a(n) <= (n-1)! for n > 0.
Showing 1-6 of 6 results.