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.

A325505 Heinz number of the set of Heinz numbers of all strict integer partitions of n.

Original entry on oeis.org

2, 3, 5, 143, 493, 62651, 26718511, 22017033127, 44220524211551, 52289759420183033963, 546407750301194131199484983, 8362548333129019658779663581495109, 1828111016191440393570169991636207115709029581, 1059934964500839879758659437301868941873808925011368355891
Offset: 0

Views

Author

Gus Wiseman, May 07 2019

Keywords

Comments

The Heinz number of a set or sequence (y_1,...,y_k) is prime(y_1)*...*prime(y_k).
Also Heinz numbers of rows of A246867 (squarefree numbers arranged by sum of prime indices A056239).

Examples

			The strict integer partitions of 5 are {(5), (4,1), (3,2)}, with Heinz numbers {11,14,15}, with Heinz number prime(11)*prime(14)*prime(15) = 62651, so a(6) = 62651.
The sequence of terms together with their prime indices begins:
                            2: {1}
                            3: {2}
                            5: {3}
                          143: {5,6}
                          493: {7,10}
                        62651: {11,14,15}
                     26718511: {13,21,22,30}
                  22017033127: {17,26,33,35,42}
               44220524211551: {19,34,39,55,66,70}
         52289759420183033963: {23,38,51,65,77,78,105,110}
  546407750301194131199484983: {29,46,57,85,91,102,130,154,165,210}
		

Crossrefs

Programs

  • Mathematica
    Table[Times@@Prime/@(Times@@Prime/@#&/@Select[IntegerPartitions[n],UnsameQ@@#&]),{n,7}]

Formula

a(n) = Product_{i = 1..A000009(n)} prime(A246867(n,i)).
A001221(a(n)) = A001222(a(n)) = A000009(n).
A056239(a(n)) = A147655(n).
A003963(a(n)) = A325506(n).