Concepts2
∑MathAdvanced
Generating Functions - EGF
Exponential generating functions (EGFs) encode a sequence (a_n) as A(x) = \sum_{n \ge 0} a_n \frac{x^n}{n!}, which naturally models labeled combinatorial objects.
#exponential generating function#egf#binomial convolution+11
∑MathAdvanced
Stirling Numbers of Second Kind
Stirling numbers of the second kind S(n,k) count how many ways to split n labeled items into k non-empty, unlabeled groups.
#stirling numbers of the second kind#set partitions#bell numbers+12