# Sequence defined on multisets

 Importance: Medium ✭✭
 Author(s): Erickson, Martin
 Subject: Combinatorics
 Keywords: multiset sequence
 Posted by: Martin Erickson on: June 29th, 2010
Conjecture   Define a array of positive integers where the first row consists of some distinct positive integers arranged in increasing order, and the second row consists of any positive integers in any order. Create a new array where the first row consists of all the integers that occur in the first array, arranged in increasing order, and the second row consists of their multiplicities. Repeat the process. For example, starting with the array , the sequence is: -> -> -> -> -> -> -> -> -> -> -> , and we now have a fixed point (loop of one array).

The process always results in a loop of 1, 2, or 3 arrays.

## Bibliography

* Erickson, Martin J., "Introduction to Combinatorics," Wiley, 1996.

* indicates original appearance(s) of problem.

### Solution

This problem has recently been solved by the author.