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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A340031 Irregular triangle read by rows T(n,k) in which row n lists n blocks, where the m-th block consists of A000041(m-1) copies of the j-th row of triangle A127093, where j = n - m + 1 and 1 <= m <= n.

Original entry on oeis.org

1, 1, 2, 1, 1, 0, 3, 1, 2, 1, 1, 1, 2, 0, 4, 1, 0, 3, 1, 2, 1, 2, 1, 1, 1, 1, 0, 0, 0, 5, 1, 2, 0, 4, 1, 0, 3, 1, 0, 3, 1, 2, 1, 2, 1, 2, 1, 1, 1, 1, 1, 1, 2, 3, 0, 0, 6, 1, 0, 0, 0, 5, 1, 2, 0, 4, 1, 2, 0, 4, 1, 0, 3, 1, 0, 3, 1, 0, 3, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 1, 1, 1, 1, 1, 1
Offset: 1

Views

Author

Omar E. Pol, Dec 26 2020

Keywords

Comments

Another version of A338156 which is the main sequence with further information about the correspondence divisor/part.

Examples

			Triangle begins:
[1];
[1,2],      [1];
[1,0,3],    [1,2],    [1],    [1];
[1,2,0,4],  [1,0,3],  [1,2],  [1,2],  [1],  [1],  [1];
[1,0,0,0,5],[1,2,0,4],[1,0,3],[1,0,3],[1,2],[1,2],[1,2],[1],[1],[1],[1],[1];
[...
Written as an irregular tetrahedron the first five slices are:
[1],
-------
[1, 2],
[1],
----------
[1, 0, 3],
[1, 2],
[1],
[1];
-------------
[1, 2, 0, 4],
[1, 0, 3],
[1, 2],
[1, 2],
[1],
[1],
[1];
----------------
[1, 0, 0, 0, 5],
[1, 2, 0, 4],
[1, 0, 3],
[1, 0, 3],
[1, 2],
[1, 2],
[1, 2],
[1],
[1],
[1],
[1],
[1];
.
The following table formed by three zones shows the correspondence between divisors and parts (n = 1..5):
.
|---|---------|-----|-------|---------|-----------|-------------|
| n |         |  1  |   2   |    3    |     4     |      5      |
|---|---------|-----|-------|---------|-----------|-------------|
| P |         |     |       |         |           |             |
| A |         |     |       |         |           |             |
| R |         |     |       |         |           |             |
| T |         |     |       |         |           |  5          |
| I |         |     |       |         |           |  3 2        |
| T |         |     |       |         |  4        |  4 1        |
| I |         |     |       |         |  2 2      |  2 2 1      |
| O |         |     |       |  3      |  3 1      |  3 1 1      |
| N |         |     |  2    |  2 1    |  2 1 1    |  2 1 1 1    |
| S |         |  1  |  1 1  |  1 1 1  |  1 1 1 1  |  1 1 1 1 1  |
|---|---------|-----|-------|---------|-----------|-------------|
.
|---|---------|-----|-------|---------|-----------|-------------|
|   | A181187 |  1  |  3 1  |  6 2 1  | 12 5 2 1  | 20 8 4 2 1  |
| L |         |  |  |  |/|  |  |/|/|  |  |/|/|/|  |  |/|/|/|/|  |
| I | A066633 |  1  |  2 1  |  4 1 1  |  7 3 1 1  | 12 4 2 1 1  |
| N |         |  *  |  * *  |  * * *  |  * * * *  |  * * * * *  |
| K | A002260 |  1  |  1 2  |  1 2 3  |  1 2 3 4  |  1 2 3 4 5  |
|   |         |  =  |  = =  |  = = =  |  = = = =  |  = = = = =  |
|   | A138785 |  1  |  2 2  |  4 2 3  |  7 6 3 4  | 12 8 6 4 5  |
|---|---------|-----|-------|---------|-----------|-------------|
.
|---|---------|-----|-------|---------|-----------|-------------|
|   | A127093 |  1  |  1 2  |  1 0 3  |  1 2 0 4  |  1 0 0 0 5  |
|   |---------|-----|-------|---------|-----------|-------------|
|   | A127093 |     |  1    |  1 2    |  1 0 3    |  1 2 0 4    |
|   |---------|-----|-------|---------|-----------|-------------|
| D | A127093 |     |       |  1      |  1 2      |  1 0 3      |
| I | A127093 |     |       |  1      |  1 2      |  1 0 3      |
| V |---------|-----|-------|---------|-----------|-------------|
| I | A127093 |     |       |         |  1        |  1 2        |
| S | A127093 |     |       |         |  1        |  1 2        |
| O | A127093 |     |       |         |  1        |  1 2        |
| R |---------|-----|-------|---------|-----------|-------------|
| S | A127093 |     |       |         |           |  1          |
|   | A127093 |     |       |         |           |  1          |
|   | A127093 |     |       |         |           |  1          |
|   | A127093 |     |       |         |           |  1          |
|   | A127093 |     |       |         |           |  1          |
|---|---------|-----|-------|---------|-----------|-------------|
.
The table is essentially the same table of A338156 but here, in the lower zone, every row is A127093 instead of A027750.
.
		

Crossrefs

Programs

  • Mathematica
    A127093row[n_]:=Table[Boole[Divisible[n,k]]k,{k,n}];
    A340031row[n_]:=Flatten[Table[ConstantArray[A127093row[n-m+1],PartitionsP[m-1]],{m,n}]];
    Array[A340031row,7] (* Paolo Xausa, Sep 28 2023 *)

A127094 Triangle, reversal of A127093.

Original entry on oeis.org

1, 2, 1, 3, 0, 1, 4, 0, 2, 1, 5, 0, 0, 0, 1, 6, 0, 0, 3, 2, 1, 7, 0, 0, 0, 0, 0, 1, 8, 0, 0, 0, 4, 0, 2, 1, 9, 0, 0, 0, 0, 0, 3, 0, 1, 10, 0, 0, 0, 0, 5, 0, 0, 2, 1, 11, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1
Offset: 1

Views

Author

Gary W. Adamson, Jan 05 2007

Keywords

Examples

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

Crossrefs

Cf. A000203 (row sums), A126988, A127093.

Programs

  • Magma
    [n mod (k-n-1) - (n+1) mod (k-n-1) + 1: k in [1..n], n in [1..12]]; // G. C. Greubel, Mar 08 2021
  • Mathematica
    Table[Mod[n, k-n-1] - Mod[n+1, k-n-1] +1, {n,12}, {k,n}]//Flatten (* G. C. Greubel, Mar 08 2021 *)
  • Sage
    flatten([[n%(k-n-1) - (n+1)%(k-n-1) + 1 for k in [1..n]] for n in [1..12]]) # G. C. Greubel, Mar 08 2021
    

Formula

Reversed rows of A127093.
T(n, K) = mod(n, k-n-1) - mod(n+1, k-n-1) + 1. - Mats Granvik, Sep 02 2007

A340011 Irregular triangle read by rows T(n,k) in which row n lists n blocks, where the m-th block consists of the j-th row of triangle A127093 but with every term multiplied by A000041(m-1), where j = n - m + 1 and 1 <= m <= n.

Original entry on oeis.org

1, 1, 2, 1, 1, 0, 3, 1, 2, 2, 1, 2, 0, 4, 1, 0, 3, 2, 4, 3, 1, 0, 0, 0, 5, 1, 2, 0, 4, 2, 0, 6, 3, 6, 5, 1, 2, 3, 0, 0, 6, 1, 0, 0, 0, 5, 2, 4, 0, 8, 3, 0, 9, 5, 10, 7, 1, 0, 0, 0, 0, 0, 7, 1, 2, 3, 0, 0, 6, 2, 0, 0, 0, 10, 3, 6, 0, 12, 5, 0, 15, 7, 14, 11, 1, 2, 0, 4, 0, 0, 0, 8
Offset: 1

Views

Author

Omar E. Pol, Dec 26 2020

Keywords

Comments

This triangle is a condensed version of the more irregular triangle A340031.
For further information about the correspondence divisor/part see A338156.

Examples

			Triangle begins:
[1];
[1, 2],          [1];
[1, 0, 3],       [1, 2],       [2];
[1, 2, 0, 4],    [1, 0, 3],    [2, 4],    [3];
[1, 0, 0, 0, 5], [1, 2, 0, 4], [2, 0, 6], [3, 6], [5];
[...
Row sums give A066186.
Written as an irregular tetrahedron the first five slices are:
--
1;
-----
1, 2,
1;
--------
1, 0, 3,
1, 2,
2;
-----------
1, 2, 0, 4,
1, 0, 3,
2, 4,
3;
--------------
1, 0, 0, 0, 5,
1, 2, 0, 4,
2, 0, 6,
3, 6,
5;
--------------
Row sums give A339106.
The following table formed by four zones shows the correspondence between divisor and parts (n = 1..5):
.
|---|---------|-----|-------|---------|-----------|-------------|
| n |         |  1  |   2   |    3    |     4     |      5      |
|---|---------|-----|-------|---------|-----------|-------------|
| P |         |     |       |         |           |             |
| A |         |     |       |         |           |             |
| R |         |     |       |         |           |             |
| T |         |     |       |         |           |  5          |
| I |         |     |       |         |           |  3 2        |
| T |         |     |       |         |  4        |  4 1        |
| I |         |     |       |         |  2 2      |  2 2 1      |
| O |         |     |       |  3      |  3 1      |  3 1 1      |
| N |         |     |  2    |  2 1    |  2 1 1    |  2 1 1 1    |
| S |         |  1  |  1 1  |  1 1 1  |  1 1 1 1  |  1 1 1 1 1  |
|---|---------|-----|-------|---------|-----------|-------------|
.
|---|---------|-----|-------|---------|-----------|-------------|
|   | A181187 |  1  |  3 1  |  6 2 1  | 12 5 2 1  | 20 8 4 2 1  |
| L |         |  |  |  |/|  |  |/|/|  |  |/|/|/|  |  |/|/|/|/|  |
| I | A066633 |  1  |  2 1  |  4 1 1  |  7 3 1 1  | 12 4 2 1 1  |
| N |         |  *  |  * *  |  * * *  |  * * * *  |  * * * * *  |
| K | A002260 |  1  |  1 2  |  1 2 3  |  1 2 3 4  |  1 2 3 4 5  |
|   |         |  =  |  = =  |  = = =  |  = = = =  |  = = = = =  |
|   | A138785 |  1  |  2 2  |  4 2 3  |  7 6 3 4  | 12 8 6 4 5  |
|---|---------|-----|-------|---------|-----------|-------------|
.
|---|---------|-----|-------|---------|-----------|-------------|
|   | A127093 |  1  |  1 2  |  1 0 3  |  1 2 0 4  |  1 0 0 0 5  |
|   |---------|-----|-------|---------|-----------|-------------|
|   | A127093 |     |  1    |  1 2    |  1 0 3    |  1 2 0 4    |
|   |---------|-----|-------|---------|-----------|-------------|
| D | A127093 |     |       |  1      |  1 2      |  1 0 3      |
| I | A127093 |     |       |  1      |  1 2      |  1 0 3      |
| V |---------|-----|-------|---------|-----------|-------------|
| I | A127093 |     |       |         |  1        |  1 2        |
| S | A127093 |     |       |         |  1        |  1 2        |
| O | A127093 |     |       |         |  1        |  1 2        |
| R |---------|-----|-------|---------|-----------|-------------|
| S | A127093 |     |       |         |           |  1          |
|   | A127093 |     |       |         |           |  1          |
|   | A127093 |     |       |         |           |  1          |
|   | A127093 |     |       |         |           |  1          |
|   | A127093 |     |       |         |           |  1          |
|---|---------|-----|-------|---------|-----------|-------------|
.
|---|---------|-----|-------|---------|-----------|-------------|
|   | A127093 |  1  |  1 2  |  1 0 3  |  1 2 0 4  |  1 0 0 0 5  |
| C | A127093 |     |  1    |  1 2    |  1 0 3    |  1 2 0 4    |
| O |    -    |     |       |  2      |  2 4      |  2 0 6      |
| N |    -    |     |       |         |  3        |  3 6        |
| D |    -    |     |       |         |           |  5          |
|---|---------|-----|-------|---------|-----------|-------------|
.
This lower zone of the table is a condensed version of the "divisors" zone.
		

Crossrefs

Programs

A340032 Irregular triangle read by rows T(n,k) in which row n lists n blocks, where the m-th block consists of A000041(n-m) copies of the row m of triangle A127093, with 1 <= m <= n.

Original entry on oeis.org

1, 1, 1, 2, 1, 1, 1, 2, 1, 0, 3, 1, 1, 1, 1, 2, 1, 2, 1, 0, 3, 1, 2, 0, 4, 1, 1, 1, 1, 1, 1, 2, 1, 2, 1, 2, 1, 0, 3, 1, 0, 3, 1, 2, 0, 4, 1, 0, 0, 0, 5, 1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 0, 3, 1, 0, 3, 1, 0, 3, 1, 2, 0, 4, 1, 2, 0, 4, 1, 0, 0, 0, 5, 1, 2, 3, 0, 0, 6
Offset: 1

Views

Author

Omar E. Pol, Dec 26 2020

Keywords

Comments

For further information about the correspondence divisor/part see A338156.

Examples

			Triangle begins:
  1;
  1, 1, 2;
  1, 1, 1, 2, 1, 0, 3;
  1, 1, 1, 1, 2, 1, 2, 1, 0, 3, 1, 2, 0, 4;
  1, 1, 1, 1, 1, 1, 2, 1, 2, 1, 2, 1, 0, 3, 1, 0, 3, 1, 2, 0, 4, 1, 0, 0, 0, 5;
  ...
Written as an irregular tetrahedron the first five slices are:
  1;
  --
  1,
  1, 2;
  -----
  1,
  1,
  1, 2,
  1, 0, 3;
  --------
  1,
  1,
  1,
  1, 2,
  1, 2,
  1, 0, 3,
  1, 2, 0, 4;
  -----------
  1,
  1,
  1,
  1,
  1,
  1, 2,
  1, 2,
  1, 2,
  1, 0, 3,
  1, 0, 3,
  1, 2, 0, 4,
  1, 0, 0, 0, 5;
  --------------
  ...
The slices of the tetrahedron appear in the upper zone of the following table (formed by three zones) which shows the correspondence between divisors and parts (n = 1..5):
.
|---|---------|-----|-------|---------|-----------|-------------|
| n |         |  1  |   2   |    3    |     4     |      5      |
|---|---------|-----|-------|---------|-----------|-------------|
|   | A127093 |     |       |         |           |  1          |
|   | A127093 |     |       |         |           |  1          |
|   | A127093 |     |       |         |           |  1          |
|   | A127093 |     |       |         |           |  1          |
| D | A127093 |     |       |         |           |  1          |
| I |---------|-----|-------|---------|-----------|-------------|
| V | A127093 |     |       |         |  1        |  1 2        |
| I | A127093 |     |       |         |  1        |  1 2        |
| S | A127093 |     |       |         |  1        |  1 2        |
| O |---------|-----|-------|---------|-----------|-------------|
| R | A127093 |     |       |  1      |  1 2      |  1 0 3      |
| S | A127093 |     |       |  1      |  1 2      |  1 0 3      |
|   |---------|-----|-------|---------|-----------|-------------|
|   | A127093 |     |  1    |  1 2    |  1 0 3    |  1 2 0 4    |
|   |---------|-----|-------|---------|-----------|-------------|
|   | A127093 |  1  |  1 2  |  1 0 3  |  1 2 0 4  |  1 0 0 0 5  |
|---|---------|-----|-------|---------|-----------|-------------|
.
|---|---------|-----|-------|---------|-----------|-------------|
|   | A138785 |  1  |  2 2  |  4 2 3  |  7 6 3 4  | 12 8 6 4 5  |
|   |         |  =  |  = =  |  = = =  |  = = = =  |  = = = = =  |
| L | A002260 |  1  |  1 2  |  1 2 3  |  1 2 3 4  |  1 2 3 4 5  |
| I |         |  *  |  * *  |  * * *  |  * * * *  |  * * * * *  |
| N | A066633 |  1  |  2 1  |  4 1 1  |  7 3 1 1  | 12 4 2 1 1  |
| K |         |  |  |  |\|  |  |\|\|  |  |\|\|\|  |  |\|\|\|\|  |
|   | A181187 |  1  |  3 1  |  6 2 1  | 12 5 2 1  | 20 8 4 2 1  |
|---|---------|-----|-------|---------|-----------|-------------|
.
|---|---------|-----|-------|---------|-----------|-------------|
| P |         |  1  |  1 1  |  1 1 1  |  1 1 1 1  |  1 1 1 1 1  |
| A |         |     |  2    |  2 1    |  2 1 1    |  2 1 1 1    |
| R |         |     |       |  3      |  3 1      |  3 1 1      |
| T |         |     |       |         |  2 2      |  2 2 1      |
| I |         |     |       |         |  4        |  4 1        |
| T |         |     |       |         |           |  3 2        |
| I |         |     |       |         |           |  5          |
| O |         |     |       |         |           |             |
| N |         |     |       |         |           |             |
| S |         |     |       |         |           |             |
|---|---------|-----|-------|---------|-----------|-------------|
.
The table is essentially the same table of A340035 but here, in the upper zone, every row is A127093 instead of A027750.
Also the above table is the table of A340031 upside down.
		

Crossrefs

Programs

  • Mathematica
    A127093row[n_]:=Table[Boole[Divisible[n,k]]k,{k,n}];
    A340032row[n_]:=Flatten[Table[ConstantArray[A127093row[m],PartitionsP[n-m]],{m,n}]];
    Array[A340032row,7] (* Paolo Xausa, Sep 28 2023 *)

A127098 Triangle T(n,m) read by rows: product A127093 * A127094.

Original entry on oeis.org

1, 5, 2, 10, 0, 3, 21, 2, 8, 4, 26, 0, 0, 0, 5, 50, 2, 3, 18, 12, 6, 50, 0, 0, 0, 0, 0, 7, 85, 2, 8, 4, 32, 0, 16, 8, 91, 0, 3, 0, 0, 0, 27, 0, 9, 130, 2, 0, 0, 5, 50, 0, 0, 20, 10, 122, 0, 0, 0, 0, 0, 0, 0, 0, 0, 11, 210, 2, 11, 22, 12, 6, 72, 0, 48, 36, 24, 12, 170, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 13, 250, 2, 0, 0, 0, 0, 7, 98, 0
Offset: 1

Views

Author

Gary W. Adamson, Jan 05 2007

Keywords

Comments

A127097 is a close companion.

Examples

			First few rows of the triangle are:
1;
5, 2;
10, 0, 3;
21, 2, 8, 4;
26, 0, 0, 0, 5;
50, 2, 3, 18, 12, 6;
50, 0, 0, 0, 0, 0, 7;
85, 2, 8, 4, 32, 0, 16, 8;
		

Crossrefs

Programs

  • Maple
    A127093 := proc(n,m) if m> n or m<1 or n < 1 then 0 ; elif (n mod m) = 0 then m; else 0 ; fi; end:
    A127094 := proc(n,m) A127093(n,n-m+1) ; end: A127098 := proc(n,m) add( A127093(n,k)*A127094(k,m),k=1..n) ; end:
    for n from 1 to 30 do for m from 1 to n do printf("%d,",A127098(n,m)) ; od: od: # R. J. Mathar, Mar 02 2009

Formula

T(n,m) = Sum_{k=m..n} A127093(n,k)*A127094(k,m).
Row sums: Sum_{m=1..n} T(n,m) = A001001(n).
Left column: T(1,m) = A001157(m).

Extensions

Edited and extended by R. J. Mathar, Mar 02 2009

A127097 Triangle T(n,m) = A127093 * A126988 read by rows.

Original entry on oeis.org

1, 5, 2, 10, 0, 3, 21, 10, 0, 4, 26, 0, 0, 0, 5, 50, 20, 15, 0, 0, 6, 50, 0, 0, 0, 0, 0, 7, 85, 42, 0, 20, 0, 0, 0, 8, 91, 0, 30, 0, 0, 0, 0, 0, 9, 130, 52, 0, 0, 25, 0, 0, 0, 0, 10, 122, 0, 0, 0, 0, 0, 0, 0, 0, 0, 11, 210, 100, 63, 40, 0, 30, 0, 0, 0, 0, 0, 12, 170, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
Offset: 1

Views

Author

Gary W. Adamson, Jan 05 2007

Keywords

Comments

Multiply the infinite lower triangular matrices A127093 and A126988.

Examples

			First few rows of the triangle are:
1;
5, 2;
10, 0, 3;
21, 10, 0, 4;
26, 0, 0, 0, 5;
50, 20, 15, 0, 0, 6;
50, 0, 0, 0, 0, 0, 7;
...
		

Crossrefs

Programs

  • Maple
    A127093 := proc(n,m) if n mod m = 0 then m; else 0 ; fi; end:
    A126988 := proc(n,k) if n mod k = 0 then n/k; else 0; fi; end:
    A127097 := proc(n,m) add( A127093(n,j)*A126988(j,m),j=m..n) ; end:
    for n from 1 to 15 do for m from 1 to n do printf("%d,",A127097(n,m)) ; od: od: # R. J. Mathar, Aug 18 2009

Formula

T(n,m) = sum_{j=m..n} A127093(n,j)*A126988(j,m).
T(n,1) = A001157(n).

Extensions

A-numbers corrected by R. J. Mathar, Aug 18 2009

A127099 Triangle T(n,m) = A126988 *A127093 read by rows.

Original entry on oeis.org

1, 3, 2, 4, 0, 3, 7, 6, 0, 4, 6, 0, 0, 0, 5, 12, 8, 9, 0, 0, 6, 8, 0, 0, 0, 0, 0, 7, 15, 14, 0, 12, 0, 0, 0, 8, 13, 0, 12, 0, 0, 0, 0, 0, 9, 18, 12, 0, 0, 15, 0, 0, 0, 0, 10, 12, 0, 0, 0, 0, 0, 0, 0, 0, 0, 11, 28, 24, 21, 16, 0, 18, 0, 0, 0, 0, 0, 12, 14, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 13, 24, 16, 0, 0
Offset: 1

Views

Author

Gary W. Adamson, Jan 05 2007

Keywords

Comments

Multiply the infinite lower triangular matrices A126988 and A127093.

Examples

			First few rows of the triangle are:
1;
3, 2;
4, 0, 3;
7, 6, 0, 4;
6, 0, 0, 0, 5;
12, 8, 9, 0, 0, 6;
8, 0, 0, 0, 0, 0, 7;
15, 14, 0, 12, 0, 0, 0, 8;
13, 0, 12, 0, 0, 0, 0, 0, 9;
18, 12, 0, 0, 15, 0, 0, 0, 0, 10;
...
		

Crossrefs

Formula

T(n,m) = sum_{j=m..n} A126988(n,j)*A127093(j,m).
T(n,1) = A000203(n).

Extensions

Extended by R. J. Mathar, Aug 18 2009

A130055 A129691 * A127093.

Original entry on oeis.org

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

Views

Author

Gary W. Adamson, May 04 2007

Keywords

Comments

Row sums = d(n), A000005: (1, 2, 2, 3, 2, 4, 2, 4, 3, 4, ...). Left column = A130054: (1, 0, -1, -1, -3, 0, -5, -2, -3, 0, ...).

Examples

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

Crossrefs

Formula

A129691 * A127093 as infinite lower triangular matrices.

A134559 A127093 * A000012.

Original entry on oeis.org

1, 3, 2, 4, 3, 3, 7, 6, 4, 4, 6, 5, 5, 5, 5, 12, 11, 9, 6, 6, 6, 8, 7, 7, 7, 7, 7, 7, 15, 14, 12, 12, 8, 8, 8, 8, 13, 12, 12, 9, 9, 9, 9, 9, 9, 18, 17, 15, 15, 15, 10, 10, 10, 10, 10
Offset: 1

Views

Author

Gary W. Adamson, Oct 31 2007

Keywords

Comments

Row sums = A001157: (1, 5, 10, 21, 26, 50, ...). Left border = sigma(n), A000203.
From Lechoslaw Ratajczak, Nov 01 2019: (Start)
Let b_n(k) (n = 1,2,3,...) be consecutive finite sequences defined as follows: b_n(k) is the sum of all integers u satisfying the equation: n mod u = k (1 <= u <= n, k = 0,1,2,...,ceiling(n/2)-1). These sequences are consecutive antidiagonals of the triangle (b_n(k) = T(n-k,k+1)).
The example for n = 8 (k_max = ceiling(8/2) - 1 = 3):
- b_8(0) = T(8-0,0+1) = T(8,1) = 15 = sigma(8) because 8 mod {1,2,4,8} = 0 and 1+2+4+8 = 15;
- b_8(1) = T(8-1,1+1) = T(7,2) = 7 = A039653(8-1) because 8 mod 7 = 1;
- b_8(2) = T(8-2,2+1) = T(6,3) = 9 because 8 mod {3,6} = 2 and 3+6 = 9;
- b_8(3) = T(8-3,3+1) = T(5,4) = 5 because 8 mod 5 = 3.
Conjecture: let P(n) be the n-th antidiagonal product (P(n) = Product_{k=0..ceiling(n/2)-1} b_n(k)). Consecutive n satisfying two equations: gcd(P(n),n) = 1 and gcd(P(n+1),n+1) = 2 are consecutive elements of A005383 (primes p such that (p+1)/2 are also primes, save A005383(1) = 3 and A005383(2) = 5). The conjecture is false if for any prime number p belonging to A005383 gcd(P(p),p) = p. The conjecture was checked for 2000 consecutive integers. (End)

Examples

			First few rows of the triangle are:
   1;
   3,  2;
   4,  3,  3;
   7,  6,  4,  4;
   6,  5,  5,  5, 5;
  12, 11,  9,  6, 6, 6;
   8,  7,  7,  7, 7, 7, 7;
  15, 14, 12, 12, 8, 8, 8, 8;
  ...
		

Crossrefs

Formula

A127093 * A000012 as infinite lower triangular matrices. Triangle read by rows, partial sums of A127093 terms starting from the right.

A253951 A partial double sum of integers: a(n) = Sum_{x=1..n} Sum_{y=1..n} T(x,y), where T is the matrix product: T = A051731*A127093*Transpose(A054524) and T(n,1)=0 (* stands for matrix multiplication).

Original entry on oeis.org

0, 1, 5, 9, 20, 23, 42, 52, 69, 77, 113, 119, 165, 177, 190, 214, 279, 291, 366, 379, 399, 422, 517, 533, 599, 625, 679, 701, 829, 846, 986, 1035, 1069, 1105, 1137, 1164, 1339, 1380, 1417, 1449, 1646, 1674, 1883, 1918, 1955, 2008, 2239, 2274, 2420, 2462, 2515, 2559, 2827, 2874, 2929
Offset: 1

Views

Author

Mats Granvik, Jan 20 2015

Keywords

Comments

a(n) ~ log(A003418(n))*n, based on the comment by Hans Havermann in A048272 referring to an argument by Gareth McCaughan.
The exact relation is: lim_{n->Infinity} log(A003418(k))*n = Sum_{x=1..n} Sum_{y=1..k} T(x,y), where T is the matrix product: T = A051731*A127093*Transpose(A054524) and T(n,1)=0.
Compare a(n) to round(log(A003418)*n)= 0, 1, 5, 10, 20, 25, 42, 54, 70, 78,...

Programs

  • Maple
    with(LinearAlgebra):
    N:= 200:
    A051731:= Matrix(N,N,(n,k) -> `if`(n mod k = 0, 1, 0),shape=triangular[lower]):
    A127093:= Matrix(N,N,(n,k) -> `if`(n mod k = 0, k, 0), shape=triangular[lower]):
    A054524T:= Matrix(N,N,(k,n) -> `if`(n mod k = 0, numtheory:-mobius(k),0), shape=triangular[upper]):
    T:= A051731 . A127093 . A054524T:
    a[1]:= 0:
    for n from 2 to N do
      a[n]:= a[n-1] + add(T[i,n],i=1..n) + add(T[n,j],j=2..n-1)
    od:
    seq(a[n],n=1..N); # Robert Israel, Jan 20 2015
  • Mathematica
    nn = 55;
    Z = Table[ If[ Mod[n, k] == 0, 1, 0], {n, nn}, {k, nn}];
    A = Table[ If[ Mod[n, k] == 0, k, 0], {n, nn}, {k, nn}];
    B = Table[ If[ Mod[n, k] == 0, MoebiusMu[k], 0], {n, nn}, {k, nn}];
    MatrixForm[T = Z.A.Transpose[B]];
    T[[All, 1]] = 0;
    a = Table[ Total[ T[[1 ;; n, 1 ;; n]], 2], {n, nn}]
    (* shows a graph *) Show[ ListLinePlot[a], ListLinePlot[ Accumulate[ MangoldtLambda[ Range[ nn]]]]]

Formula

a(n) = Sum_{x=1..n} Sum_{y=1..n} T(x,y), where T is the matrix product: T=A051731*A127093*Transpose(A054524) and T(n,1)=0. (* stands for matrix multiplication)
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