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.

A321650 Irregular triangle whose n-th row is the reversed conjugate of the integer partition with Heinz number n.

Original entry on oeis.org

1, 1, 1, 2, 1, 1, 1, 1, 2, 1, 1, 1, 1, 3, 2, 2, 1, 1, 2, 1, 1, 1, 1, 1, 1, 3, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 2, 2, 4, 1, 1, 1, 1, 1, 1, 1, 2, 3, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 3, 1, 1, 2, 2, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 4, 2, 2, 2, 1, 1, 1, 1
Offset: 1

Views

Author

Gus Wiseman, Nov 15 2018

Keywords

Comments

The Heinz number of an integer partition (y_1, ..., y_k) is prime(y_1) * ... * prime(y_k).

Examples

			Triangle begins:
  1
  1 1
  2
  1 1 1
  1 2
  1 1 1 1
  3
  2 2
  1 1 2
  1 1 1 1 1
  1 3
  1 1 1 1 1 1
  1 1 1 2
  1 2 2
  4
  1 1 1 1 1 1 1
  2 3
  1 1 1 1 1 1 1 1
  1 1 3
  1 1 2 2
  1 1 1 1 2
  1 1 1 1 1 1 1 1 1
The sequence of reversed dual partitions begins: (), (1), (11), (2), (111), (12), (1111), (3), (22), (112), (11111), (13), (111111), (1112), (122), (4), (1111111), (23), (11111111), (113), (1122), (11112), (111111111), (14), (222), (111112), (33), (1113), (1111111111), (123).
		

Crossrefs

Programs

  • Mathematica
    primeMS[n_]:=If[n==1,{},Flatten[Cases[FactorInteger[n],{p_,k_}:>Table[PrimePi[p],{k}]]]];
    conj[y_]:=If[Length[y]==0,y,Table[Length[Select[y,#>=k&]],{k,1,Max[y]}]];
    Table[Sort[conj[primeMS[n]]],{n,50}]

Formula

a(n,i) = A112798(A122111(n),i).