# Bell numbers

From Encyclopedia of Mathematics

The Bell numbers are given by

or by

Also,

where are Stirling numbers (cf. Combinatorial analysis) of the second kind, so that is the total number of partitions of an -set.

They are equal to .

The name honours E.T. Bell.

#### References

[a1] | L. Comtet, "Advanced combinatorics" , Reidel (1974) |

**How to Cite This Entry:**

Bell numbers.

*Encyclopedia of Mathematics.*URL: http://encyclopediaofmath.org/index.php?title=Bell_numbers&oldid=14335

This article was adapted from an original article by N.J.A. Sloane (originator), which appeared in Encyclopedia of Mathematics - ISBN 1402006098. See original article