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.

Previous Showing 11-18 of 18 results.

A144199 Square array (8 X 8) read by rows.

Original entry on oeis.org

0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 1, 0, 0, 0, 0, 0, 0
Offset: 1

Views

Author

Mats Granvik, Sep 13 2008

Keywords

Comments

Permutation contributing to the determinant that gives the 4th value of the Möbius function. Determinant of matrix is equal to 1. The array is asymmetrical.

Examples

			The array is:
0,0,0,0,0,0,0,1
1,0,0,0,0,0,0,0
0,0,1,0,0,0,0,0
0,0,0,1,0,0,0,0
0,0,0,0,1,0,0,0
0,0,0,0,0,1,0,0
0,0,0,0,0,0,1,0
0,1,0,0,0,0,0,0
		

Crossrefs

A144200 Square array (8 X 8) read by rows.

Original entry on oeis.org

0, 0, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0
Offset: 1

Views

Author

Mats Granvik, Sep 13 2008

Keywords

Comments

Permutation contributing to the determinant that gives the 8th value of the Möbius function. Determinant of matrix is equal to 1. The array is asymmetrical.

Examples

			The array is:
0,0,0,0,0,0,0,1
0,1,0,0,0,0,0,0
0,0,1,0,0,0,0,0
1,0,0,0,0,0,0,0
0,0,0,0,1,0,0,0
0,0,0,0,0,1,0,0
0,0,0,0,0,0,1,0
0,0,0,1,0,0,0,0
		

Crossrefs

A144201 Square array (8 X 8) read by rows.

Original entry on oeis.org

0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0
Offset: 1

Views

Author

Mats Granvik, Sep 13 2008

Keywords

Comments

Permutation contributing to the determinant that gives the 8th value of the Möbius function. Determinant of matrix is equal to -1. The array is asymmetrical.

Examples

			The array is:
0,0,0,0,0,0,0,1
1,0,0,0,0,0,0,0
0,0,1,0,0,0,0,0
0,1,0,0,0,0,0,0
0,0,0,0,1,0,0,0
0,0,0,0,0,1,0,0
0,0,0,0,0,0,1,0
0,0,0,1,0,0,0,0
		

Crossrefs

A144194 Square array (6 X 6) read by rows.

Original entry on oeis.org

0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0
Offset: 1

Views

Author

Mats Granvik, Sep 13 2008

Keywords

Comments

Permutation contributing to the determinant that gives the 6th value of the Möbius function. Determinant of matrix is equal to -1. The array is symmetrical.

Examples

			The array is:
0,0,0,0,0,1
0,1,0,0,0,0
0,0,1,0,0,0
0,0,0,1,0,0
0,0,0,0,1,0
1,0,0,0,0,0
		

Crossrefs

A174856 Square array read by antidiagonals up. Redheffer type matrix. T(1,1)=1 and T(n,1) = A049240.

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 0, 0, 0, 1, 1, 1, 1, 0, 1, 1, 0, 0, 0, 0, 1, 1, 1, 0, 1, 0, 0, 1, 1, 0, 1, 0, 0, 0, 0, 1, 0, 1, 0, 0, 1, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 0, 1, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 1, 0, 1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1
Offset: 1

Views

Author

Mats Granvik, Mar 31 2010

Keywords

Comments

The first column is equal to 0 when n is a square greater than 1. The rest of the array is equal to A143104. The determinant of this array is A002819.

Examples

			The array begins:
  1,1,1,1,1,1,1,1,1,1
  1,1,0,0,0,0,0,0,0,0
  1,0,1,0,0,0,0,0,0,0
  0,1,0,1,0,0,0,0,0,0
  1,0,0,0,1,0,0,0,0,0
  1,1,1,0,0,1,0,0,0,0
  1,0,0,0,0,0,1,0,0,0
  1,1,0,1,0,0,0,1,0,0
  0,0,1,0,0,0,0,0,1,0
  1,1,0,0,1,0,0,0,0,1
		

Crossrefs

Programs

  • Mathematica
    t[1, 1] = 1; t[n_, 1] := Boole[!IntegerQ[Sqrt[n]]]; t[n_, k_] := Boole[n == 1 || Mod[n, k] == 0]; Table[t[n - k + 1, k], {n, 1, 14}, {k, 1, n}] // Flatten (* Jean-François Alcover, Dec 05 2013 *)

A144966 Square array T(n,k) read by antidiagonals up. A055615 interleaved with k-1 zeros in each column. Redheffer type matrix.

Original entry on oeis.org

1, -2, 1, -3, 1, 1, 0, 0, 0, 1, -5, -2, 1, 0, 1, 6, 0, 0, 0, 0, 1, -7, -3, 0, 1, 0, 0, 1, 0, 0, -2, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 1, 10, 0, 0, 0, 0, 0, 0, 0, 0, 1, -11, -5, -3, -2, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -13, 6, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 14, 0, 0, 0, -2, 0
Offset: 1

Views

Author

Mats Granvik, Sep 27 2008

Keywords

Comments

Determinant of this array appears to be the triangular numbers. The number of permutations that contribute to the result of the zero corner determinant that give the natural numbers, appears to be given by A002033.

Examples

			Determinant of:
1
is equal to 1.
Determinant of:
1,1
-2,0
is equal to 2.
Determinant of:
1,1,1
-2,1,0
-3,0,0
is equal to 3.
Determinant of:
1,1,1,1
-2,1,0,0
-3,0,1,0
0,-2,0,0
is equal to 4.
Determinant of:
1,1,1,1,1
-2,1,0,0,0
-3,0,1,0,0
0,-2,0,1,0
-5,0,0,0,0
is equal to 5.
Determinant of:
1,1,1,1,1,1
-2,1,0,0,0,0
-3,0,1,0,0,0
0,-2,0,1,0,0
-5,0,0,0,1,0
6,-3,-2,0,0,0
is equal to 6.
		

Crossrefs

Programs

  • Excel
    =if(mod(row(); column())=0; lookup(row()/column(); A000027; A055615); if(row()=1; 1; 0))

A145110 Number of elements in the Redheffer matrix that contribute to the Moebius function.

Original entry on oeis.org

1, 2, 3, 6, 5, 10, 7, 13, 11, 14
Offset: 1

Views

Author

Mats Granvik, Oct 02 2008

Keywords

Comments

a(11) to a(30) are conjectured to be 11, 23, 13, 18, 19, 25, 17, 29, 19, 30, 26, 26, 23, 45, 27, 30, 32, 39, 29, 48. [From Mats Granvik, Dec 21 2008]

Examples

			Contribution from _Mats Granvik_, Dec 21 2008: (Start)
The contributing elements for a(8) are:
0,0,0,0,0,0,0,1
1,1,0,0,0,0,0,0
0,0,1,0,0,0,0,0
1,1,0,1,0,0,0,0
0,0,0,0,1,0,0,0
0,0,0,0,0,1,0,0
0,0,0,0,0,0,1,0
1,1,0,1,0,0,0,0
where rows 8, 4 and 2 are included because they are divisors of 8. The sum of this array is 13, therefore a(8) = 13. (End)
		

Crossrefs

Extensions

a(9)-a(10) from Mats Granvik, Oct 05 2008
Moved conjectured terms a(11)-a(30) to Comments. - N. J. A. Sloane, May 22 2014

A145379 Square array read by antidiagonals upwards: T(n,k) = 1 if n divides k, T(n,k) = 0 otherwise, n >= 1, k >= 2.

Original entry on oeis.org

1, 1, 1, 0, 0, 1, 0, 1, 1, 1, 0, 0, 0, 0, 1, 0, 0, 1, 0, 1, 1, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1, 0, 1, 0, 0, 0, 0, 0, 0
Offset: 1

Views

Author

Mats Granvik, Oct 09 2008

Keywords

Comments

This array is used in the proof of the Moebius function as a zero corner determinant of the Redheffer matrix. This table is the transpose of A051731 where the first row has been deleted.

Examples

			Table begins:
1,1,1,1,1,1,1,...
1,0,1,0,1,0,1,...
0,1,0,0,1,0,0,...
0,0,1,0,0,0,1,...
0,0,0,1,0,0,0,...
0,0,0,0,1,0,0,...
0,0,0,0,0,1,0,...
...
		

Crossrefs

Programs

  • Excel
    =if(mod(column()+1;row())=0;1;0)
Previous Showing 11-18 of 18 results.