A135010 -id:A135010 - cp's OEIS frontend

A339304 Irregular triangle read by rows T(n,k) in which row n has length the partition number A000041(n-1) and columns k give the number of divisors function A000005, 1 <= k <= n.

1, 2, 2, 1, 3, 2, 1, 2, 2, 2, 1, 1, 4, 3, 2, 2, 2, 1, 1, 2, 2, 3, 2, 2, 2, 2, 1, 1, 1, 1, 4, 4, 2, 3, 3, 2, 2, 2, 2, 2, 2, 1, 1, 1, 1, 3, 2, 4, 2, 2, 3, 3, 2, 2, 2, 2, 2, 2, 2, 2, 1, 1, 1, 1, 1, 1, 1, 4, 4, 2, 4, 4, 2, 2, 3, 3, 3, 3, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 1, 1, 1, 1, 1, 1, 1, 1

Offset: 1

Omar E. Pol, Nov 29 2020

T(n,k) is also the number of divisors of A336811(n,k).

Conjecture: the sum of row n equals A138137(n), the total number of parts in the last section of the set of partitions of n.

			Triangle begins:
  1;
  2;
  2, 1;
  3, 2, 1;
  2, 2, 2, 1, 1;
  4, 3, 2, 2, 2, 1, 1;
  2, 2, 3, 2, 2, 2, 2, 1, 1, 1, 1;
  4, 4, 2, 3, 3, 2, 2, 2, 2, 2, 2, 1, 1, 1, 1;
  3, 2, 4, 2, 2, 3, 3, 2, 2, 2, 2, 2, 2, 2, 2, 1, 1, 1, 1, 1, 1, 1;
  ...

Paolo Xausa, Table of n, a(n) for n = 1..11732 (rows 1..27 of the triangle, flattened)

Number of divisors of A336811.
Row n has length A000041(n-1).
Every column gives A000005.
Row sums give A138137 (conjectured).
Cf. A135010, A138121, A138879, A187219.

A339304row[n_]:=Flatten[Table[ConstantArray[DivisorSigma[0,n-m],PartitionsP[m]-PartitionsP[m-1]],{m,0,n-1}]];Array[A339304row,10] (* Paolo Xausa, Sep 01 2023 *)

a(m) = A000005(A336811(m)).

T(n,k) = A000005(A336811(n,k)).

A182738 Partial sums of A066186.

Original entry on oeis.org

1, 5, 14, 34, 69, 135, 240, 416, 686, 1106, 1722, 2646, 3959, 5849, 8489, 12185, 17234, 24164, 33474, 46014, 62646, 84690, 113555, 151355, 200305, 263641, 344911, 449015, 581400, 749520, 961622, 1228790, 1563509, 1982049

Offset: 1

Omar E. Pol, Jan 22 2011

a(n) is also the volume of a three-dimensional version of the section model of partitions: the 3D illustrations in A135010 show boxes with face areas of 1 X 1, 2 X 2, 3 X 3, 4 X 5, 5 X 7 units along the m and p(m) axis, which is sequence A066186. Assuming that the boxes are 1 unit deep, the total volume of all boxes up to layer n is a(n). See the first two links.
From Omar E. Pol, Jan 20 2021: (Start)
a(n) is the sum of all parts of all partitions of all positive integers <= n.
Convolution of A000203 and A000070.
Convolution of A024916 and A000041.
Convolution of A175254 and A002865.
Convolution of A340793 and A014153.
Row sums of triangles A340527, A340531, A340579.
Consider a symmetric tower (a polycube) in which the terraces are the symmetric representation of sigma (n..1) respectively starting from the base (cf. A237270, A237593). The total area of the terraces equals A024916(n), the same as the area of the base.
The levels of the terraces starting from the base are the first n terms of A000070, that is A000070(0)..A000070(n-1), hence the differences between two successive levels give the partition numbers A000041, that is A000041(0)..A000041(n-1).
a(n) is the volume (or the total number of unit cubes) of the polycube.
That is due to the correspondence between divisors and partitions (cf. A336811).
The symmetric tower is a member of the family of the pyramid described in A245092.
The growth of the volume of the polycube represents every convolution mentioned above. (End)

			a(6) = 135 because the volume V(6) = p(1) + 2*p(2) + 3*p(3) + 4*p(4) + 5*p(5) + 6*p(6) = 1 + 2*2 + 3*3 + 4*5 + 5*7 + 6*11 = 1 + 4 + 9 + 20 + 35 + 66 = 135 where p(n) = A000041(n).

Vaclav Kotesovec, Table of n, a(n) for n = 1..10000
Omar E. Pol, Illustration of a(6) = 135, the polycube contains 135 unit cubes.
Omar E. Pol, Illustration of a(9) = 686, the polycube contains 686 unit cubes.

Cf. A000041, A000070, A000203, A002865, A014153, A024916, A066186, A135010, A175254, A237270, A237593, A245092, A336811, A340527, A340531, A340579, A340793.

With[{no=35},Accumulate[PartitionsP[Range[no]]Range[no]]] (* Harvey P. Dale, Feb 02 2011 *)

a(n) = n*A000070(n) - A014153(n-1). - Vaclav Kotesovec, Jun 23 2015
a(n) ~ sqrt(n) * exp(Pi*sqrt(2*n/3)) / (Pi*2^(3/2)) * (1 + (11*Pi/(24*sqrt(6)) - sqrt(6)/Pi)/sqrt(n) + (73*Pi^2/6912 - 3/16)/n). - Vaclav Kotesovec, Jun 23 2015, extended Nov 04 2016
G.f.: x*f'(x)/(1 - x), where f(x) = Product_{k>=1} 1/(1 - x^k). - Ilya Gutkovskiy, Apr 10 2017

A211009 Triangle read by rows: T(n,k) = number of cells in the k-column of the n-th region of j in the list of colexicographically ordered partitions of j, if 1<=n<=A000041(j), 1<=k<=A141285(n).

Original entry on oeis.org

1, 1, 2, 1, 1, 3, 1, 1, 1, 1, 2, 5, 1, 1, 1, 1, 1, 1, 2, 7, 1, 1, 1, 1, 2, 2, 1, 1, 1, 1, 1, 1, 2, 4, 11, 1, 1, 1, 1, 1, 1, 2, 2, 1, 1, 1, 1, 1, 1, 1, 1, 2, 4, 15, 1, 1, 1, 1, 2, 2, 1, 1, 1, 1, 1, 1, 2, 4, 4, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 3, 7, 22

Offset: 1

Omar E. Pol, Oct 21 2012

Also the finite sequence a(1)..a(r), where a(r) is a record in the sequence, is also a finite triangle read by rows: T(n,k) = number of cells in the k-column of the n-th region of the integer whose number of partitions is equal to a(r).
T(n,k) is also 1 plus the number of holes between T(n,k) and the previous member in the column k of triangle.
T(n,k) is also the height of the column mentioned in the definition, in a three-dimensional model of the set of partitions of j, in which the regions appear rotated 90 degrees and where the pivots are the largest part of every region (see A141285). For the definition of "region" see A206437. - Omar E. Pol, Feb 06 2014

			The irregular triangle begins:
1;
1, 2;
1, 1, 3;
1, 1;
1, 1, 2, 5;
1, 1, 1;
1, 1, 1, 2, 7;
1, 1;
1, 1, 2, 2;
1, 1, 1;
1, 1, 1, 2, 4, 11;
1, 1, 1;
1, 1, 1, 2, 2;
1, 1, 1, 1;
1, 1, 1, 1, 2, 4, 15;
1, 1;
1, 1, 2, 2;
1, 1, 1;
1, 1, 1, 2, 4, 4;
1, 1, 1, 1, 1;
1, 1, 1, 1;
1, 1, 1, 1, 2, 3, 7, 22;
...
From _Omar E. Pol_, Feb 06 2014: (Start)
Illustration of initial terms:
.    _
.   |_|
.    1
.      _
.    _|_|
.   |_ _|
.    1 2
.        _
.       |_|
.    _ _|_|
.   |_ _ _|
.    1 1 3
.    _ _
.   |_ _|
.    1 1
.          _
.         |_|
.         |_|
.        _|_|
.    _ _|_ _|
.   |_ _ _ _|
.    1 1 2 5
.
(End)

Omar E. Pol, Illustration of the seven regions of 5

Records give positive terms of A000041. Row n has length A141285(n). Row sums give A186412.

Cf. A040051, A135010, A182244, A182703, A186114, A187219, A193870, A194446, A206437.

Better definition from Omar E. Pol, Feb 06 2014

A182732 The limit of row A182730(n,.) as n-> infinity.

Original entry on oeis.org

2, 4, 3, 6, 5, 4, 8, 4, 7, 6, 5, 10, 3, 6, 5, 9, 4, 8, 7, 6, 12, 5, 4, 8, 7, 6, 11, 6, 5, 10, 9, 8, 7, 14, 4, 7, 6, 5, 10, 5, 9, 8, 7, 13, 4, 8, 7, 6, 12, 6, 11, 10, 9, 8, 16, 3, 6, 5, 9, 4, 8, 7, 6, 12, 7, 6, 11, 5, 10, 9, 8, 15, 6, 5, 10, 9, 8, 7, 14, 8, 7, 13, 6, 12, 11, 10, 9, 18

Offset: 1

Omar E. Pol, Nov 28 2010

nonn

Largest part of the n-th partition of the table 2.0 mentioned in A135010. For the table 2.0 see A182982.

Omar E. Pol, Illustration of the shell model of partitions (3D view)

One together with where records occur give A182746.

Cf. A135010, A138121, A141285, A151285, A182730, A182731, A182733, A182982, A182983.

A182733 The limit of row A182731(n,.) as n-> infinity.

Original entry on oeis.org

3, 5, 4, 7, 3, 6, 5, 9, 5, 4, 8, 7, 6, 11, 4, 7, 6, 5, 10, 5, 9, 8, 7, 13, 3, 6, 5, 9, 4, 8, 7, 6, 12, 7, 6, 11, 5, 10, 9, 8, 15, 5, 4, 8, 7, 6, 11, 6, 5, 10, 9, 8, 7, 14, 5, 9, 8, 7, 13, 7, 6, 12, 11, 10, 9, 17, 4, 7, 6, 5, 10, 5, 9, 8, 7, 13, 4, 8, 7, 6, 12, 6, 11, 10, 9, 8, 16, 7, 6, 11, 5, 10, 9, 8, 15, 9, 8, 7, 14, 7, 13, 12, 11, 10, 19

Offset: 1

Omar E. Pol, Nov 28 2010

nonn

Largest part of the n-th partition of the table 2.1 mentioned in A135010. For the table 2.1 see A182983.

Omar E. Pol, Illustration of the shell model of partitions (3D view)

Zero together with where records occur give A182747.

Cf. A135010, A138121, A141285, A182730, A183731, A182732, A182982, A182983.

A194438 Triangle read by rows: T(n,k) is the number of regions of the set of partitions of n into k parts.

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 2, 1, 1, 0, 1, 3, 1, 1, 0, 1, 0, 1, 5, 2, 1, 0, 1, 0, 1, 0, 0, 0, 1, 7, 3, 1, 0, 1, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 11, 4, 1, 1, 1, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 1, 15, 6, 1, 2, 1, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0

Offset: 1

Omar E. Pol, Nov 28 2011

For the definition of "region" see A206437. See also A186114 and A193870. - Omar E. Pol, May 21 2021

			Triangle begins:
   1;
   1,1;
   1,1,1;
   2,1,1,0,1;
   3,1,1,0,1,0,1;
   5,2,1,0,1,0,1,0,0,0,1;
   7,3,1,0,1,0,1,0,0,0,1,0,0,0,1;
  11,4,1,1,1,0,1,0,0,0,1,0,0,0,1,0,0,0,0,0,0,1;
...

Omar E. Pol, Illustration of the seven regions of 5

Column 1 is A194439.
Row n has length A000041(n).
Row sums give A000041, n >= 1.
Cf. A008284, A135010, A138121, A186114, A186412, A193870, A194436, A194437, A194439, A194446, A194447, A206437.

Definition clarified by Omar E. Pol, May 21 2021

A194437 Triangle read by rows: T(n,k) = sum of parts in the k-th region of n.

Original entry on oeis.org

1, 1, 3, 1, 3, 5, 1, 3, 5, 2, 9, 1, 3, 5, 2, 9, 3, 12, 1, 3, 5, 2, 9, 3, 12, 2, 6, 3, 20, 1, 3, 5, 2, 9, 3, 12, 2, 6, 3, 20, 3, 7, 4, 25, 1, 3, 5, 2, 9, 3, 12, 2, 6, 3, 20, 3, 7, 4, 25, 2, 6, 3, 13, 5, 4, 38, 1, 3, 5, 2, 9, 3, 12, 2, 6, 3, 20, 3, 7

Offset: 1

Omar E. Pol, Nov 27 2011

			Triangle begins:
1;
1,3;
1,3,5;
1,3,5,2,9;
1,3,5,2,9,3,12;
1,3,5,2,9,3,12,2,6,3,20;
1,3,5,2,9,3,12,2,6,3,20,3,7,4,25;
1,3,5,2,9,3,12,2,6,3,20,3,7,4,25,2,6,3,13,5,4,38;
...
Row n has length A000041(n). Row sums give A066186. Right border gives A046746. Records in every row give A046746. Rows converge to A186412.

Cf. A046746, A066186, A135010, A138121, A186114, A186412, A193870, A194436, A194438, A194439, A194446, A194447.

A194805 Number of parts that are visible in one of the three views of the section model of partitions version "tree" with n sections.

Original entry on oeis.org

0, 1, 2, 4, 7, 11, 17, 25, 36, 51, 71, 97, 132, 177, 235, 310, 406, 527, 681, 874, 1116, 1418, 1793, 2256, 2829, 3532, 4393, 5445, 6727, 8282, 10168, 12445, 15190, 18491, 22452, 27192, 32859, 39613, 47651, 57199, 68522, 81920, 97756, 116434, 138435

Offset: 0

Omar E. Pol, Jan 27 2012

nonn

The mentioned view of the section model looks like a tree (see example). Note that every column contains the same parts. For more information about the section model of partitions see A135010 and A194803.

Number of partitions of 2n-1 such that n-1 or n is a part, for n >=1. - Clark Kimberling, Mar 01 2014

			Illustration of one of the three views with seven sections:
.
.                   1
.                 2 1
.                   1 3
.                 2 1
.               4   1
.                   1 3
.                   1   5
.                 2 1
.               4   1
.             3     1
.           6       1
.                     3
.                       5
.                         4
.                           7
.
There are 25 parts that are visible, so a(7) = 25.
Using the formula we have a(7) = p(7) + p(7-1) - 1 = 15 + 11 - 1 = 25, where p(n) is the number of partitions of n.

Robert Price, Table of n, a(n) for n = 0..5000

Cf. A000041, A000065, A084376, A135010, A138121, A141285, A194550, A194803, A194804.

Table[Count[IntegerPartitions[2 n - 1],  p_ /; Or[MemberQ[p, n - 1], MemberQ[p, n]]], {n, 50}]  (* Clark Kimberling, Mar 01 2014 *)
Table[PartitionsP[n] + PartitionsP[n-1] - 1, {n, 0, 44}] (* Robert Price, May 12 2020 *)

a(n) = A084376(n) - 1.
a(n) = A000041(n) + A000041(n-1) - 1, if n >= 1.
a(n) = A000041(n) + A000065(n-1), if n >= 1.

A207380 Total area of the shadows of the three views of a three-dimensional version of the shell model of partitions with n shells.

Original entry on oeis.org

0, 3, 10, 21, 42, 70, 122, 187, 298, 443, 667, 957, 1401, 1960, 2775, 3828, 5295, 7167, 9745, 12998, 17380, 22915, 30196, 39347, 51274, 66126, 85209, 108942, 139055, 176273, 223148, 280733, 352623, 440646, 549597, 682411, 845852, 1044084, 1286512, 1579582

Offset: 0

Omar E. Pol, Feb 17 2012

nonn

In this model each part of a partition can be represented by a cuboid of size 1 x 1 x L, where L is the size of the part. One of the views is a rectangle formed by ones whose area is n*A000041(n) = A066186(n). Each element of the first view is equal to the volume of a horizontal column parallel to the axis x. The second view is the n-th slice illustrated in A026792 which has A000041(n) levels and its area is A006128(n) equals the total number of parts of all partitions of n and equals the sum of largest parts of all partitions of n. Each zone contains a partition of n. Each element of the second view is equal to the volume of a horizontal column parallel to the axis y. The third view is a triangle because it is also the n-th slice of the tetrahedron of A209655. The area of triangle is A000217(n). Each element of the third view is equal to the volume of a vertical column parallel to the axis z. The sum of elements of each view is A066186(n) equals the area of the first view. For more information about the shell model of partitions see A135010 and A182703.

			For n = 5 the three views of the three-dimensional shell model of partitions with 5 shells look like this:
.
.   A066186(5) = 35     A006128(5) = 20
.
.         1 1 1 1 1     5
.         1 1 1 1 1     3 2
.         1 1 1 1 1     4 1
.         1 1 1 1 1     2 2 1
.         1 1 1 1 1     3 1 1
.         1 1 1 1 1     2 1 1 1
.         1 1 1 1 1     1 1 1 1 1
.
.
.         7 6 4 2 1
.           1 2 3 2
.             1 1 2
.               1 1
.                 1
.
.   A000217(5) = 15
.
The areas of the shadows of the three views are A066186(5) = 35, A006128(5) = 20 and A000217(5) = 15, therefore the total area of the three shadows is 35+20+15 = 70, so a(5) = 70.

Alois P. Heinz, Table of n, a(n) for n = 0..1000

Other versions: A210970, A210979, A210980, A210990, A210991.

Cf. A000041, A000217, A006128, A026792, A066186, A135010, A138121, A141285, A182703, A182715, A206437, A209655.

b:= proc(n, i) option remember; local f, g;
      if n=0 or i=1 then [1, n]
    else f:= b(n, i-1); g:= `if`(i>n, [0, 0], b(n-i, i));
         [f[1]+g[1], f[2]+g[2]+g[1]]
      fi
    end:
a:= n-> n*b(n, n)[1] +b(n, n)[2] +n*(n+1)/2:
seq (a(n), n=0..50);  # Alois P. Heinz, Mar 22 2012

b[n_, i_] := b[n, i] = Module[{f, g}, If [n == 0 || i == 1, {1, n}, f = b[n, i-1]; g = If[i>n, {0, 0}, b[n-i, i]]; Join[f[[1]] + g[[1]], f[[2]] + g[[2]] + g[[1]] ]]]; a[n_] := n*b[n, n][[1]] + b[n, n][[2]] + n*(n+1)/2; Table[a[n], {n, 0, 50}] (* Jean-François Alcover, Jun 18 2015, after Alois P. Heinz *)

a(n) = n * A000041(n) + A000217(n) + A006128(n) = A066186(n) + A000217(n) + A006128(n).

More terms from Alois P. Heinz, Mar 22 2012

A210970 Total area of the shadows of the three views of a three-dimensional version of the shell model of partitions with n shells.

Original entry on oeis.org

0, 3, 9, 18, 34, 55, 91, 136, 208, 301, 439, 616, 876, 1203, 1665, 2256, 3062, 4083, 5459, 7186, 9470, 12335, 16051, 20688, 26648, 34027, 43395, 54966, 69496, 87341, 109591, 136766, 170382, 211293, 261519, 322382, 396694, 486327, 595143, 725954, 883912

Offset: 0

Omar E. Pol, Apr 22 2012

nonn

For more information see A135010 and A182703.

			For n = 6 the illustration of the three views of a three-dimensional version of the shell model of partitions with 6 shells looks like this:
.
.   A006128(6) = 35     A006128(6) = 35
.
.                 6     6
.               3 3     3 3
.               4 2     4 2
.             2 2 2     2 2 2
.               5 1     5 1
.             3 2 1     3 2 1
.             4 1 1     4 1 1
.           2 2 1 1     2 2 1 1
.           3 1 1 1     3 1 1 1
.         2 1 1 1 1     2 1 1 1 1
.       1 1 1 1 1 1     1 1 1 1 1 1
.
.
.       1 2 5 9 12 6  \
.         1 1 3 5 6    \
.           1 1 2 4     \ 6th slice of
.             1 1 2     / tetrahedron A210961
.               1 1    /
.                 1   /
.
.      A000217(6) = 21
.
The areas of the shadows of the three views are A006128(6) = 35, A006128(6) = 35 and A000217(6) = 21, therefore the total area of the three shadows is 35+35+21 = 91, so a(6) = 91.

Other versions: A207380, A210979, A210980, A210990, A210991.

Cf. A000217, A006128, A066186, A135010, A138121, A182703, A206437, A210952, A210961.

a(n) = 2*A006128(n) + A000217(n).

cp's OEIS Frontend

A339304 Irregular triangle read by rows T(n,k) in which row n has length the partition number A000041(n-1) and columns k give the number of divisors function A000005, 1 <= k <= n.

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A182738 Partial sums of A066186.

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A211009 Triangle read by rows: T(n,k) = number of cells in the k-column of the n-th region of j in the list of colexicographically ordered partitions of j, if 1<=n<=A000041(j), 1<=k<=A141285(n).

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A182732 The limit of row A182730(n,.) as n-> infinity.

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A182733 The limit of row A182731(n,.) as n-> infinity.

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A194438 Triangle read by rows: T(n,k) is the number of regions of the set of partitions of n into k parts.

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A194437 Triangle read by rows: T(n,k) = sum of parts in the k-th region of n.

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A194805 Number of parts that are visible in one of the three views of the section model of partitions version "tree" with n sections.

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A207380 Total area of the shadows of the three views of a three-dimensional version of the shell model of partitions with n shells.

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