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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A218572 Number of partitions p of n such that max(p)-min(p) = 9.

Original entry on oeis.org

1, 1, 3, 3, 7, 8, 14, 18, 28, 35, 53, 66, 92, 117, 157, 196, 259, 319, 411, 507, 638, 777, 970, 1171, 1438, 1728, 2098, 2501, 3012, 3563, 4251, 5008, 5923, 6931, 8152, 9486, 11078, 12835, 14900, 17177, 19844, 22768, 26169, 29916, 34219, 38954, 44387, 50338
Offset: 11

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Author

Alois P. Heinz, Nov 02 2012

Keywords

Programs

  • Mathematica
    terms = 48; offset = 11; max = terms + offset; s[k0_ /; k0 > 0] := Sum[x^(2*k + k0)/Product[ (1 - x^(k + j)), {j, 0, k0}], {k, 1, Ceiling[max/2]}] + O[x]^max // CoefficientList[#, x] &; Drop[s[9], offset] (* Jean-François Alcover, Sep 11 2017, after Alois P. Heinz *)

Formula

G.f.: Sum_{k>0} x^(2*k+9)/Product_{j=0..9} (1-x^(k+j)).
a(n) = A097364(n,9) = A116685(n,9) = A194621(n,9) - A194621(n,8) = A218511(n) - A218510(n).

A244966 Triangle read by rows: T(n,k) is the difference between the largest and the smallest part of the k-th partition in the list of colexicographically ordered partitions of n, with n>=1 and 1<=k<=p(n), where p(n) is the number of partitions of n.

Original entry on oeis.org

0, 0, 0, 0, 1, 0, 0, 1, 2, 0, 0, 0, 1, 2, 1, 3, 1, 0, 0, 1, 2, 1, 3, 2, 4, 0, 2, 0, 0, 0, 1, 2, 1, 3, 2, 4, 1, 3, 2, 5, 1, 3, 1, 0, 0, 1, 2, 1, 3, 2, 4, 1, 3, 2, 5, 2, 4, 3, 6, 0, 2, 1, 4, 2, 0, 0, 0, 1, 2, 1, 3, 2, 4, 1, 3, 2, 5, 2, 4, 3, 6, 1, 3, 2, 5, 4, 3, 7, 1, 3, 2, 5, 0, 3, 1, 0
Offset: 1

Views

Author

Omar E. Pol, Jul 18 2014

Keywords

Comments

The number of t's in row n gives A097364(n,t), with n>=1 and 0<=t
Rows converge to A244967, which is A141285 - 1.
Row n has length A000041(n).
Row sums give A116686.

Examples

			Triangle begins:
0;
0, 0;
0, 1, 0;
0, 1, 2, 0, 0;
0, 1, 2, 1, 3, 1, 0;
0, 1, 2, 1, 3, 2, 4, 0, 2, 0, 0;
0, 1, 2, 1, 3, 2, 4, 1, 3, 2, 5, 1, 3, 1, 0;
0, 1, 2, 1, 3, 2, 4, 1, 3, 2, 5, 2, 4, 3, 6, 0, 2, 1, 4, 2, 0, 0;
...
For n = 6 we have:
--------------------------------------------------------
.                        Largest  Smallest   Difference
k    Partition of 6        part     part       T(6,k)
--------------------------------------------------------
1:  [1, 1, 1, 1, 1, 1]      1    -    1     =     0
2:  [2, 1, 1, 1, 1]         2    -    1     =     1
3:  [3, 1, 1, 1]            3    -    1     =     2
4:  [2, 2, 1, 1]            2    -    1     =     1
5:  [4, 1, 1]               4    -    1     =     3
6:  [3, 2, 1]               3    -    1     =     2
7:  [5, 1]                  5    -    1     =     4
8:  [2, 2, 2]               2    -    2     =     0
9:  [4, 2]                  4    -    2     =     2
10: [3, 3]                  3    -    3     =     0
11: [6]                     6    -    6     =     0
--------------------------------------------------------
So the 6th row of triangle is [0,1,2,1,3,2,4,0,2,0,0] and the row sum is A116686(6) = 15.
Note that in the 6th row there are four 0's so A097364(6,0) = 4, there are two 1's so A097364(6,1) = 2, there are three 2's so A097364(6,2) = 3, there is only one 3 so A097364(6,3) = 1, there is only one 4 so A097364(6,4) = 1 and there are no 5's so A097364(6,5) = 0.
		

Formula

T(n,k) = A141285(k) - A196931(n,k), n>=1, 1<=k<=A000041(n).

A244967 A141285(n) - 1.

Original entry on oeis.org

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

Author

Omar E. Pol, Jul 18 2014

Keywords

Comments

The rows of the triangle in A244966 converge to this sequence.

Crossrefs

A361862 Number of integer partitions of n such that (maximum) - (minimum) = (mean).

Original entry on oeis.org

0, 0, 0, 1, 0, 1, 0, 3, 2, 2, 0, 7, 0, 3, 6, 10, 0, 13, 0, 17, 10, 5, 0, 40, 12, 6, 18, 34, 0, 62, 0, 50, 24, 8, 60, 125, 0, 9, 32, 169, 0, 165, 0, 95, 176, 11, 0, 373, 114, 198, 54, 143, 0, 384, 254, 574, 66, 14, 0, 1090, 0, 15, 748, 633, 448, 782, 0, 286
Offset: 1

Author

Gus Wiseman, Apr 10 2023

Keywords

Comments

In terms of partition diagrams, these are partitions whose rectangle from the left (length times minimum) has the same size as the complement.

Examples

			The a(4) = 1 through a(12) = 7 partitions:
  (31)  .  (321)  .  (62)    (441)  (32221)  .  (93)
                     (3221)  (522)  (33211)     (642)
                     (3311)                     (4431)
                                                (5322)
                                                (322221)
                                                (332211)
                                                (333111)
The partition y = (4,4,3,1) has maximum 4 and minimum 1 and mean 3, and 4 - 1 = 3, so y is counted under a(12). The diagram of y is:
  o o o o
  o o o o
  o o o .
  o . . .
Both the rectangle from the left and the complement have size 4.
		

Crossrefs

Positions of zeros are 1 and A000040.
For length instead of mean we have A237832.
For minimum instead of mean we have A118096.
These partitions have ranks A362047.
A000041 counts integer partitions, strict A000009.
A008284 counts partitions by length, A058398 by mean.
A067538 counts partitions with integer mean.
A097364 counts partitions by (maximum) - (minimum).
A243055 subtracts the least prime index from the greatest.
A326844 gives the diagram complement size of Heinz partition.

Programs

  • Mathematica
    Table[Length[Select[IntegerPartitions[n],Max@@#-Min@@#==Mean[#]&]],{n,30}]
Previous Showing 11-14 of 14 results.