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.

A327483 Triangle read by rows where T(n,k) is the number of integer partitions of 2^n with mean 2^k, 0 <= k <= n.

Original entry on oeis.org

1, 1, 1, 1, 2, 1, 1, 5, 4, 1, 1, 22, 34, 8, 1, 1, 231, 919, 249, 16, 1, 1, 8349, 112540, 55974, 1906, 32, 1, 1, 1741630, 107608848, 161410965, 4602893, 14905, 64, 1, 1, 4351078600, 1949696350591, 12623411092535, 676491536028, 461346215, 117874, 128, 1
Offset: 0

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Author

Gus Wiseman, Sep 13 2019

Keywords

Comments

T(n,k) is the number of partitions of 2^n into 2^(n-k) parts. - Chai Wah Wu, Sep 21 2023

Examples

			Triangle begins:
      1
      1       1
      1       2         1
      1       5         4         1
      1      22        34         8       1
      1     231       919       249      16     1
      1    8349    112540     55974    1906    32  1
      1 1741630 107608848 161410965 4602893 14905 64 1
      ...
		

Crossrefs

Row sums are A327484.
Column k = 1 is A068413 (shifted once to the right).

Programs

  • Mathematica
    Table[Length[Select[IntegerPartitions[2^n],Mean[#]==2^k&]],{n,0,5},{k,0,n}]
  • Python
    from sympy.utilities.iterables import partitions
    from sympy import npartitions
    def A327483_T(n,k):
        if k == 0 or k == n: return 1
        if k == n-1: return 1<Chai Wah Wu, Sep 21 2023
    
  • Python
    # uses A008284_T
    def A327483_T(n,k): return A008284_T(1<Chai Wah Wu, Sep 21 2023

Formula

T(n+1,n) = 2^n for n >= 0. - Chai Wah Wu, Sep 14 2019

Extensions

a(28)-a(35) from Chai Wah Wu, Sep 14 2019
Row n=8 from Alois P. Heinz, Sep 21 2023