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.

A330954 Number of integer partitions of n whose product is divisible by the sum of primes of their parts.

Original entry on oeis.org

0, 0, 0, 0, 0, 0, 1, 0, 2, 3, 4, 2, 3, 9, 8, 18, 15, 25, 35, 44, 50, 70, 71, 93, 141, 158, 226, 286, 337, 439, 532, 648, 789, 1013, 1261, 1454, 1776, 2176, 2701, 3258, 3823, 4606, 5521, 6613, 7810, 9202, 11074, 13145, 15498, 18413, 21818, 25774, 30481, 35718
Offset: 1

Views

Author

Gus Wiseman, Jan 15 2020

Keywords

Examples

			The a(7) = 1 through a(15) = 8 partitions (empty column not shown):
  43  63   541     83     552   6322   4433       5532
      441  4222    3332   6411  7411   7322       6522
           222211  5222         62221  44321      84111
                   33221               63311      333222
                                       65111      432222
                                       72221      3322221
                                       433211     32222211
                                       4322111    333111111
                                       322211111
For example, the partition (3,3,2,2,1) has product 3 * 3 * 2 * 2 * 1 = 36 and sum of primes 5 + 5 + 3 + 3 + 2 = 18, and 36 is divisible by 18, so (3,3,2,2,1) is counted under a(11).
		

Crossrefs

The Heinz numbers of these partitions are given by A331378.
Partitions whose product is divisible by their sum are A057568.
Numbers divisible by the sum of their prime indices are A324851.
Partitions whose sum of primes divides their product of primes are A330953.
Partitions whose sum of primes divides of their product are A331381.
Partitions whose product equals their sum of primes are A331383.

Programs

  • Mathematica
    Table[Length[Select[IntegerPartitions[n],Divisible[Times@@#,Plus@@Prime/@#]&]],{n,30}]