Number of ways to write $n$ as a sum of $k$ non-negative integers of at most $d$
65763
Number of ways to write n as a sum of k nonnegative integers
134352
The number of possible factorizations of a positive integer.
2137
Find the number of ways to express 1050 as sum of consecutive integers
71797
Combinatorial argument for $\sum\limits_{k=i}^{n}\binom{n}{k}\binom{k}{i} = \binom{n}{i}2^{n-i}$
50615
Expressing a Non Negative Integer as Sums of Two Squares
110441
Closed form for a formula with a summation over $i\binom{n-i}{k-1}$, and combinatorial proof?
7785
Cardinality of sum-set
79568
Cardinality of the set $D$
123955
How to compute $\sum\limits_{k=0}^n (-1)^k{2n-k\choose k}$?
21000
Calculating $\sum_{k=1}^nk(k!)$ combinatorially
146098
Number of nonempty subsets of a set with $n$ elements
94407
Number of solutions for $x[1] + x[2] + \ldots + x[n] =k$
119046
Expressing a positive integer as a sum of positive integers
58480
Computing sums of divisors in $O(\sqrt n)$ time?
104704
Evaluate $\sum\limits_{k=0}^n \binom{n}{k}$ combinatorially
27263
How many ways can $b$ balls be distributed in $c$ containers with no more than $n$ balls in any given container?
4559
How many ways can $133$ be written as sum of only $1s$ and $2s$