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.

A358137 Heinz number of the partial sums of the prime indices of n.

Original entry on oeis.org

1, 2, 3, 6, 5, 10, 7, 30, 21, 14, 11, 42, 13, 22, 33, 210, 17, 110, 19, 66, 39, 26, 23, 330, 65, 34, 273, 78, 29, 130, 31, 2310, 51, 38, 85, 546, 37, 46, 57, 390, 41, 170, 43, 102, 357, 58, 47, 2730, 133, 238, 69, 114, 53, 1870, 95, 510, 87, 62, 59, 714, 61
Offset: 1

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Author

Gus Wiseman, Oct 31 2022

Keywords

Comments

The Heinz number of a partition (y_1,...,y_k) is prime(y_1)*...*prime(y_k). This gives a bijective correspondence between positive integers and integer partitions.

Examples

			The terms together with their prime indices begin:
      1: {}
      2: {1}
      3: {2}
      6: {1,2}
      5: {3}
     10: {1,3}
      7: {4}
     30: {1,2,3}
     21: {2,4}
     14: {1,4}
     11: {5}
     42: {1,2,4}
     13: {6}
     22: {1,5}
     33: {2,5}
    210: {1,2,3,4}
     17: {7}
    110: {1,3,5}
		

Crossrefs

The sorted version is A325362.
The prime indices are rows of A358136, partial sums of rows of A112798.
A000040 lists the primes.
A000041 counts partitions, strict A000009.
A003963 multiplies prime indices.
A056239 adds up prime indices.

Programs

  • Mathematica
    primeMS[n_]:=If[n==1,{},Flatten[Cases[FactorInteger[n],{p_,k_}:>Table[PrimePi[p],{k}]]]];
    Table[Times@@Prime/@Accumulate[primeMS[n]],{n,100}]

Formula

A001222(a(n)) = A001222(n).