Stirling Number of the Second Kind of 1

Theorem

 * $\displaystyle \left\{ {1 \atop n}\right\} = \delta_{1 n}$

where:
 * $\displaystyle \left\{ {1 \atop n}\right\}$ denotes a Stirling number of the second kind
 * $\delta_{1 n}$ is the Kronecker delta.

Also see

 * Unsigned Stirling Number of the First Kind of 1
 * Signed Stirling Number of the First Kind of 1