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.

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A128260 A128229 * A051731.

Original entry on oeis.org

1, 2, 1, 3, 2, 1, 4, 1, 3, 1, 5, 4, 0, 4, 1, 6, 1, 1, 0, 5, 1, 7, 6, 6, 0, 0, 6, 1, 8, 1, 0, 1, 0, 0, 7, 1, 9, 8, 1, 8, 0, 0, 0, 8, 1, 10, 1, 9, 0, 1, 0, 0, 0, 9, 1
Offset: 1

Views

Author

Gary W. Adamson, Feb 21 2007

Keywords

Comments

Row sums = A128261: (1, 3, 6, 9, 14, 14, 26, 18, 35, 31, ...).

Examples

			First few rows of the triangle:
  1;
  2, 1;
  3, 2, 1;
  4, 1, 3, 1;
  5, 4, 0, 4, 1;
  6, 1, 1, 0, 5, 1;
  7, 6, 6, 0, 0, 6, 1;
  8, 1, 0, 1, 0, 0, 7, 1;
  ...
		

Crossrefs

A128382 Inverse Moebius transform operation performed 24 times on A000594: A051731^24 * A000594.

Original entry on oeis.org

1, 0, 276, -1748, 4854, 0, -16720, 44552, -107295, 0, 534636, -482448, -577714, 0, 1339704, 2528206, -6905910, 0, 10661444, -8484792, -4614720, 0, 18643296, 12296352, -25383005, 0, -75928312, 29226560, 128406654, 0, -52843144, -151821160, 147559536, 0, -81158880
Offset: 1

Views

Author

Gary W. Adamson, Feb 28 2007

Keywords

Comments

Conjecture: given the inverse Moebius transform operation performed any k times (k=1,2,3,...); k=24 is the only such sequence with zeros. A weaker conjecture: "zero" occurs an infinite number of times in A128382.
Multiplicative because A000594 is. Each application of A051731 corresponds to an inverse Moebius transform. - Andrew Howroyd, Aug 03 2018

Crossrefs

Programs

  • Mathematica
    nmax = 40;
    M = Table[If[Mod[n, k] == 0, 1, 0], {n, nmax}, {k, nmax}];
    MatrixPower[M, 24].RamanujanTau[Range[nmax]] (* Jean-François Alcover, Sep 20 2019 *)
  • PARI
    seq(n, k=24)={my(u=vector(n,n,1), v=vector(n,n,ramanujantau(n))); for(i=1, k, v=dirmul(u,v)); v} \\ Andrew Howroyd, Aug 03 2018

Formula

Dirichlet g.f.: Sum_{n>=1} a(n)/n^s = (Sum_{n>=1} A000594(n)/n^s)*zeta(s)^24. - Jianing Song, Aug 04 2018

Extensions

Terms a(11) and beyond from Andrew Howroyd, Aug 03 2018

A130162 Triangle read by rows: A051731 * A000837 as a diagonalized matrix.

Original entry on oeis.org

1, 1, 1, 1, 0, 2, 1, 1, 0, 3, 1, 0, 0, 0, 6, 1, 1, 2, 0, 0, 7, 1, 0, 0, 0, 0, 0, 14, 1, 1, 0, 3, 0, 0, 0, 17, 1, 0, 2, 0, 0, 0, 0, 0, 27, 1, 1, 0, 0, 6, 0, 0, 0, 0, 34, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 55, 1, 1, 2, 3, 0, 7, 0, 0, 0, 0, 0, 63
Offset: 1

Views

Author

Gary W. Adamson, May 13 2007

Keywords

Comments

Right border = A000837 (offset 1).
Row sums = partition numbers A000041 starting (1, 2, 3, 5, 7, ...).

Examples

			First few rows of the triangle:
  1;
  1,  1;
  1,  0,  2;
  1,  1,  0,  3;
  1,  0,  0,  0,  6;
  1,  1,  2,  0,  0,  7;
  1,  0,  0,  0,  0,  0, 14;
  1,  1,  0,  3,  0,  0,  0, 17;
  ...
		

Crossrefs

Programs

Formula

A051731 * A000837 (starting at offset 1) as a diagonalized matrix M, where M = T(n,k) = A000837(n) * 0^(n-k), 1<=k<=n; i.e., (1; 0,1; 0,0,2; 0,0,0,3; 0,0,0,0,6;...).
A051731 = inverse Moebius transform.

Extensions

More terms from Jean-François Alcover, Oct 03 2013
Offset changed to 1 by Georg Fischer, Jun 27 2023

A131088 2*A051731 - A054525 as infinite lower triangular matrices.

Original entry on oeis.org

1, 3, 1, 3, 0, 1, 2, 3, 0, 1, 3, 0, 0, 0, 1, 1, 3, 3, 0, 0, 1, 3, 0, 0, 0, 0, 0, 1, 2, 2, 0, 3, 0, 0, 0, 1, 2, 0, 3, 0, 0, 0, 0, 0, 1, 1, 3, 0, 0, 3, 0, 0, 0, 0, 1, 3, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 2, 1, 2, 3, 0, 3, 0, 0, 0, 0, 0, 1, 3, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1
Offset: 1

Views

Author

Gary W. Adamson, Jun 14 2007

Keywords

Comments

Row sums = A131089.
A131090: (1, 3, 3, 2, 3, 1, 3, 2, 2, 1, ...) in every column interspersed with (k-1) zeros.

Examples

			First few rows of the triangle:
  1;
  3, 1;
  3, 0, 1;
  2, 3, 0, 1;
  3, 0, 0, 0, 1;
  1, 3, 3, 0, 0, 1
  3, 0, 0, 0, 0, 0, 1;
  2, 2, 0, 3, 0, 0, 0, 1;
  ...
		

Crossrefs

Cf. A129979 (left border), A131089 (row sums), A051731, A054525.

Programs

  • PARI
    T(n,k) = 2*!(n%k) - if (!(n % k), moebius(n/k), 0);
    row(n) = vector(n, k, T(n,k));
    lista(nn) = for (n=1, nn, v = row(n); for (k=1, #v, print1(v[k], ", "))); \\ Michel Marcus, Feb 26 2022

Extensions

More terms from Michel Marcus, Feb 26 2022

A133699 A051731 * A133698.

Original entry on oeis.org

1, 1, 1, 1, 0, 2, 1, 1, 0, 1, 1, 0, 0, 0, 2, 1, 1, 2, 0, 0, 2, 1, 0, 0, 0, 0, 0, 2, 1, 1, 0, 1, 0, 0, 0, 1, 1, 0, 2, 0, 0, 0, 0, 0, 3, 1, 1, 0, 0, 2, 0, 0, 0, 0, 2
Offset: 1

Views

Author

Gary W. Adamson, Sep 21 2007

Keywords

Comments

Right border = A001227, the number of odd divisors of n.
Row sums = A133700: (1, 2, 3, 3, 3, 6, 3, 4, 6, 6, ...)

Examples

			First few rows of the triangle:
  1;
  1, 1;
  1, 0, 2;
  1, 1, 0, 1;
  1, 0, 0, 0, 2;
  1, 1, 2, 0, 0, 2;
  1, 0, 0, 0, 0, 0, 2;
  1, 1, 0, 1, 0, 0, 0, 1;
  ...
		

Crossrefs

Formula

Inverse Mobius transform of A133698, as infinite lower triangular matrices.

A133701 A133698 * A051731.

Original entry on oeis.org

1, 1, 1, 2, 0, 2, 1, 1, 0, 1, 2, 0, 0, 0, 2, 2, 2, 2, 0, 0, 2, 2, 0, 0, 0, 0, 0, 2, 1, 1, 0, 1, 0, 0, 0, 1, 3, 0, 3, 0, 0, 0, 0, 0, 3, 2, 2, 0, 0, 2, 0, 0, 0, 0, 2
Offset: 1

Views

Author

Gary W. Adamson, Sep 21 2007

Keywords

Comments

Left and right borders = A001227: (1, 1, 2, 1, 2, 2, 2, ...), the number of odd divisors of n.
Row sums = A133702, the inverse Mobius transform of A023136.

Examples

			First few rows of the triangle:
  1;
  1, 1;
  2, 0, 2;
  1, 1, 0, 1;
  2, 0, 0, 0, 2;
  2, 2, 2, 0, 0, 2;
  2, 0, 0, 0, 0, 0, 2;
  1, 1, 0, 1, 0, 0, 0, 1;
  ...
		

Crossrefs

Formula

A133698 * A051731 as infinite lower triangular matrices.

A133702 A051731 * A023136.

Original entry on oeis.org

1, 2, 4, 3, 4, 8, 4, 4, 9, 8, 4, 12, 4, 8, 16, 5, 6, 18, 4, 12, 16, 8, 4, 16, 9, 8, 16, 12, 4, 32, 8, 6, 16, 12, 16, 27, 4, 8, 16, 16, 6, 32, 8, 12, 36, 8, 4, 20, 9, 18, 24, 12, 4, 32, 16, 16, 16, 8, 4, 48, 4, 16, 44, 7, 20, 32, 4, 18, 16, 32, 4, 36, 10, 8, 36, 12, 16, 32, 4, 20, 25, 12, 4, 48
Offset: 1

Views

Author

Gary W. Adamson, Sep 21 2007

Keywords

Comments

A023136 = (1, 1, 3, 1, 3, 3, 3, 1, 5, 3, ...).

Examples

			a(4) = 3 = (1, 1, 0, 1) * (1, 1, 3, 1) = (1, 1, 0, 1), row 4 of triangle A133701.
		

Crossrefs

Formula

Inverse Mobius transform of A023136.

Extensions

More terms from R. J. Mathar, Jan 19 2009

A134699 Triangle read by rows: A051731^2 * A000012.

Original entry on oeis.org

1, 3, 1, 3, 1, 1, 6, 3, 1, 1, 3, 1, 1, 1, 1, 9, 5, 3, 1, 1, 1, 3, 1, 1, 1, 1, 1, 1, 10, 6, 3, 3, 1, 1, 1, 1, 6, 3, 3, 1, 1, 1, 1, 1, 1, 9, 5, 3, 3, 3, 1, 1, 1, 1, 1, 3, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 18, 12, 8, 5, 3, 3, 1, 1, 1, 1, 1, 1, 3, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1
Offset: 1

Views

Author

Gary W. Adamson, Nov 06 2007

Keywords

Comments

Left column = A007425.
Row sums = A007429: (1, 4, 5, 11, 7, 20, ...).

Examples

			First few rows of the triangle:
   1;
   3, 1;
   3, 1, 1;
   6, 3, 1, 1;
   3, 1, 1, 1, 1;
   9, 5, 3, 1, 1, 1;
   3, 1, 1, 1, 1, 1, 1;
  10, 6, 3, 3, 1, 1, 1, 1;
  ...
		

Crossrefs

Formula

A051731^2 * A000012 = A127170 * A000012, as infinite lower triangular matrices.

Extensions

More terms from Jinyuan Wang, Apr 29 2025

A137587 Triangle read by rows: A051731 * A026794.

Original entry on oeis.org

1, 2, 1, 3, 0, 1, 5, 2, 0, 1, 6, 1, 0, 0, 1, 11, 3, 2, 0, 0, 1, 12, 2, 1, 0, 0, 0, 1, 20, 6, 1, 2, 0, 0, 0, 1, 25, 4, 3, 1, 0, 0, 0, 0, 1, 37, 9, 2, 1, 2, 0, 0, 0, 0, 1, 43, 8, 3, 1, 1, 0, 0, 0, 0, 0, 1, 70, 16, 6, 3, 1, 2, 0, 0, 0, 0, 0, 1
Offset: 1

Views

Author

Gary W. Adamson, Jan 27 2008

Keywords

Comments

That is, regard A051731 and A026794 as lower triangular square matrices and multiply them, then take the lower triangle of the product,
Left column = A083710 starting (1, 2, 3, 5, 6, 11, 12, ...).
Row sums = A047968.

Examples

			First few rows of the triangle:
   1;
   2, 1;
   3, 0, 1;
   5, 2, 0, 1;
   6, 1, 0, 0, 1;
  11, 3, 2, 0, 0, 1;
  12, 2, 1, 0, 0, 0, 1;
  20, 6, 1, 2, 0, 0, 0, 1;
  25, 4, 3, 1, 0, 0, 0, 0, 1;
  ...
		

Crossrefs

Formula

Inverse mobius transform of the partition triangle, A026794.

Extensions

Typo in 9th row corrected by M. F. Hasler, Jun 08 2009

A140705 A000012 * A051731^4.

Original entry on oeis.org

1, 5, 1, 9, 1, 1, 19, 5, 1, 1, 23, 5, 1, 1, 1, 39, 9, 5, 1, 1, 1, 43, 9, 5, 1, 1, 1, 1, 63, 19, 5, 5, 1, 1, 1, 1, 73, 19, 9, 5, 1, 1, 1, 1, 1, 89, 23, 9, 5, 5, 1, 1, 1, 1, 1, 93, 23, 9, 5, 5, 1, 1, 1, 1, 1, 1
Offset: 1

Views

Author

Gary W. Adamson, May 24 2008

Keywords

Comments

Row sums = A061203: (1, 6, 11, 26, 31, 56,...).
Left column = A061202: (1, 5, 9, 19, 23, 39,...).

Examples

			First few rows of the triangle are:
1;
5, 1;
9, 1, 1;
19, 5, 1, 1;
23, 5, 1, 1, 1;
39, 9, 5, 1, 1, 1;
43, 9, 5, 1, 1, 1, 1;
63, 19, 5, 5, 1, 1, 1, 1;
...
		

Crossrefs

Formula

A000012 * A051731^4 as infinite lower triangular matrices, where A051731 = the inverse Mobius transform and A000012 = an infinite lower triangular matrix with all 1's.

Extensions

a(60) split into 5,1 by Georg Fischer, Aug 27 2023
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