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.

A088216 Smallest nonnegative number not expressible as determinant of an n X n matrix with elements 1..n^2.

Original entry on oeis.org

0, 324, 38831, 6773999, 1859163031
Offset: 2

Views

Author

Hugo Pfoertner, Sep 23 2003

Keywords

Examples

			a(2)=0 because the 2 X 2 determinant of a matrix with entries that are permutations of 1,2,3,4 can only assume the values +-2,+-5,+-10.
		

Crossrefs

a(3)=A088214(1), a(4)=A088237(1), a(5)=A088238(1), a(6)=A325900(1).

Extensions

a(6) from Hugo Pfoertner, Sep 07 2019

A088217 Number of distinct values that can be assumed by the determinant of an n X n matrix whose entries are all permutations of the numbers 1..n^2.

Original entry on oeis.org

1, 6, 777, 79455, 13602389, 3722956267
Offset: 1

Views

Author

Hugo Pfoertner, Sep 23 2003

Keywords

Comments

a(5) = 1 + 2*(A085000(5) - (number of terms of A088238)).

Examples

			a(2)=6 because the determinants of the 24 2 X 2 matrices whose entries are all permutations of 1,2,3,4 can only assume the values -10,-5,-2,2,5,10.
		

Crossrefs

Programs

  • Fortran
    C See link given in A088238.
  • Mathematica
    f[n_] := (p = Permutations[ Table[i, {i, n^2}]]; Length[ Union[ Table[ Det[ Partition[ p[[i]], n]], {i, 1, (n^2)!}]]]) (* Robert G. Wilson v *)

Extensions

Minor edits and a(6) from Hugo Pfoertner, Sep 08 2019

A325900 Numbers less than the maximum possible determinant A085000(6)=1865999570 not occurring as determinant of a 6 X 6 matrix with entries {1,..,36}.

Original entry on oeis.org

1859163031, 1859166733, 1859193211, 1859235497, 1859254067, 1859268659, 1859282869, 1859288597, 1859291519, 1859294309, 1859309245, 1859317037, 1859320819, 1859324083, 1859324501, 1859331797, 1859333683, 1859335879, 1859348273, 1859348639, 1859351059, 1859358869
Offset: 1

Views

Author

Hugo Pfoertner, Sep 07 2019

Keywords

Comments

There are 4521437 terms in the sequence.

Crossrefs

Showing 1-3 of 3 results.