# Definition:Bell Number

## Definition

The Bell Numbers $B_n$ are a sequence of natural numbers defined as the number of ways a set with $n$ elements can be partitioned.

### Sequence of Bell Numbers

The sequence of Bell numbers begins:

$(1), 1, 2, 5, 15, 52, 203, 877, 4140, 21 \, 147, \ldots$

where the first $(1)$ is the zeroth Bell number $B_0$.

## Also see

• Results about Bell numbers can be found here.

## Source of Name

This entry was named for Eric Temple Bell.