| Cells n | distinct | distinct | identical | identical |
|---|
| Balls k | distinct | identical | distinct | identical |
| 0≤xi≤1, n≥k | (n−k)!n!=(n)k | (kn) | 1 | 1 |
| xi≥0 | nk | (kn+k−1) | | p(k) ^[Partition] |
| xi≥1 | n!{nk} | (n−1k−1) | | pn(k) ^[ [[Partition#Partition into k]]. Note, there, n is balls, and k is cells ] |
Shahriari, An Invitation to Combinatorics, 349.
| # | k Balls | n Cells | Order in Cell | Empty Cells | Additional Restrictions | Formula / Notation |
|---|
| 1 | Identical | Distinct | No | allowed | At most 1 per cell | (kn) if k≤n |
| 2 | Distinct | Distinct | No | allowed | At most 1 per cell | (kn)⋅k! if k≤n |
| 3 | Distinct | Distinct | No | allowed | None | nk |
| 4 | Identical | Distinct | No | allowed | None | (kn+k−1) |
| 5 | Distinct | Distinct | Yes | allowed | None | nk |
| 6 | Distinct | Distinct | No | Not allowed | None | S(k,n)⋅n! |
| 7 | Distinct | Identical | No | Not allowed | None | S(k,n) |
| 8 | Distinct | Distinct | No | Not allowed | Any number of cells | ∑i=1nS(k,i)⋅(in)⋅i! |
| 9 | Distinct | Identical | No | Not allowed | Any number of cells | ∑i=1nS(k,i) |
| 10 | Identical | Identical | No | Not allowed | None | pn(k) (partitions of k into exactly n positive integers) |
| 11 | Identical | Identical | No | Not allowed | Any number of cells | p(k) (all integer partitions of k) |