Bell numbers
From specialfunctionswiki
The Bell numbers $B_n$ are defined by the formula $$B_n = \displaystyle\sum_{k=0}^n S(n,k),$$ where $S(n,k)$ denotes the Stirling numbers of the second kind.
The Bell numbers $B_n$ are defined by the formula $$B_n = \displaystyle\sum_{k=0}^n S(n,k),$$ where $S(n,k)$ denotes the Stirling numbers of the second kind.
