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.

A234097 Combined weight, as defined at A234094, of the partitions of n.

Original entry on oeis.org

1, 5, 14, 36, 74, 153, 275, 497, 832, 1383, 2182, 3446, 5213, 7872, 11563, 16899, 24155, 34422, 48146, 67117, 92239, 126222, 170721, 230113, 306990, 408110, 538067, 706834, 921862, 1198453, 1548054, 1993462, 2552970, 3259507, 4141423, 5247231, 6618965
Offset: 1

Views

Author

Clark Kimberling, Jan 01 2014

Keywords

Comments

These are the row sums of the array at A234094, where weight is defined.

Crossrefs

Programs

  • Mathematica
    z = 40; p[n_] := p[n] = IntegerPartitions[n]; q[n_] := q[n] = Length[p[n]]; v[n_] := v[n]; w[n_, h_] := w[n, h] = Dot[p[n][[h]], v[Length[p[n][[h]]]]]; a[n_] := Sum[w[n, h], {h, 1, q[n]}]; t = Table[a[n], {n, 1, z}]

A234922 Array w(n,h), in which row n shows the weights (defined in Comments) of the partitions of n, arranged in reverse Mathematica order.

Original entry on oeis.org

1, 3, 2, 6, 5, 3, 10, 9, 6, 7, 4, 15, 14, 11, 12, 8, 9, 5, 21, 20, 17, 12, 18, 14, 9, 15, 10, 11, 6, 28, 27, 24, 19, 25, 21, 15, 16, 22, 17, 11, 18, 12, 13, 7, 36, 35, 32, 27, 20, 33, 29, 23, 24, 17, 30, 25, 18, 19, 12, 26, 20, 13, 21, 14, 15, 8, 45, 44, 41
Offset: 1

Views

Author

Clark Kimberling, Jan 01 2014

Keywords

Comments

The weight of a partition P = x(1)+ x(2)+...+x(k) of n is introduced at A234094 as k*x(1) + (k-1)*x(2) + ... + x(k).

Examples

			Represent 1+1+1+1+1 as _1_1_1_1_1_.  The partition 1+2+2 matches the placement of dividers d indicated by _1d1_1d1_1d. To place the 1st d takes 1 step (starting at the 1st '_'); to place the 2nd d takes 1+2 steps (starting at the 1st '_'); to place the 3rd d takes 1+2+2 steps. The total number of steps is 2+3+5 = 9, the 3rd number in row 5, because 1+2+2 is the 3rd partition of 5 in reverse Mathematica ordering. The first 6 rows:
1
3    2
6    5    3
10   9    6    7    4
15   14   11   12   8    9    5
21   20   17   12   18   14   9   15   10   11   6
		

Crossrefs

Programs

  • Mathematica
    p[n_] := p[n] = Reverse[IntegerPartitions[n]]; q[n_] := q[n] = Length[p[n]]; v[n_] := v[n] = Table[n + 1 - i, {i, 1, n}]; w[n_, h_] := w[n, h] = Dot[p[n][[h]], v[Length[p[n][[h]]]]];
    Flatten[Table[w[n, h], {n, 1, 9}, {h, 1, q[n]}]] (* A234094 *)
    TableForm[Table[w[n, h], {n, 1, 9}, {h, 1, q[n]}]]

Formula

w(n,h) = dot product of (partition # h of n) and (k, k-1, ..., 1), where k = length of (partition # h of n).

A234923 Array w(n,h), in which row n shows the weights, as defined in Comments, of the distinct-parts partitions of n, arranged in Mathematica order.

Original entry on oeis.org

1, 2, 3, 5, 4, 7, 5, 9, 8, 6, 11, 10, 14, 7, 13, 12, 11, 17, 8, 15, 14, 13, 20, 19, 9, 17, 16, 15, 23, 14, 22, 20, 10, 19, 18, 17, 26, 16, 25, 24, 23, 30, 11, 21, 20, 19, 29, 18, 28, 17, 27, 26, 25, 34, 12, 23, 22, 21, 32, 20, 31, 19, 30, 29, 29, 28, 38, 26
Offset: 1

Views

Author

Clark Kimberling, Jan 01 2014

Keywords

Comments

The weight of a partition P = x (1)+ x(2)+...+x(k) of n is given at A234094 as k*x(1) + (k-1)*x(2) + ... + x(k), which is the number of steps needed to make P from the sum 1+1+...+1 = n by moving dividers into the sum; see the Example section.

Examples

			Represent 1+1+1+1+1 as _1_1_1_1_1_. The partition 3+2+1 matches the placement of dividers d indicated by _1 _1_1d1_1_d_1_d. To place the 1st d takes 3 steps (starting at the 1st '_'); to place the 2nd d takes 3+2 steps (starting at the 1st '_'); to place the 3rd d takes 3+2+1 steps. The total number of steps is 3+5+6 = 14, the 4th number in row 4 because 3+2+1 is the 4th distinct-parts partition of 6 in Mathematica ordering. The first 9 rows:
1
2
3    5
4    7
5    9    8
6   11   10   14
7   13   12   11   17
8   15   14   13   20   19
9   17   16   15   23   14   22   20
		

Crossrefs

Programs

  • Mathematica
    p[n_] := p[n] = Select[IntegerPartitions[n], Max[Length /@ Split@#] == 1 &]; q[n_] := q[n] = Length[p[n]]; v[n_] := v[n] = Table[n + 1 - i, {i, 1, n}]; w[n_, h_] := w[n, h] = Dot[p[n][[h]], v[Length[p[n][[h]]]]]; Flatten[Table[w[n, h], {n, 1, 9}, {h, 1, q[n]}]]
    TableForm[Table[w[n, h], {n, 1, 9}, {h, 1, q[n]}]]

Formula

w(n,h) = dot product of (partition # h of n) and (k, k-1, ..., 1), where k = length of (partition # h of n).
Showing 1-3 of 3 results.