Combinatorics-set of divisors
158579
If $r,s,t$ are prime numbers and $p,q$ positive integers s.t. $\text{lcm}(p,q)$ is $r^2s^4t^2$, then the number of ordered pairs $(p,q)$ is?
44214
The number of subsets of a set of cardinality $n$
86051
Find the sum of reciprocals of divisors given the sum of divisors
91178
chain of divisibility relation
40538
On determinants and common divisors
82207
Number of Pairs of Subsets
11359
Determine the Set of a Sum of Numbers
22154
Show that given a set of positive n integers, there exists a non-empty subset whose sum is divisible by n
117862
Number of partitions of an $n$-element set into $k$ classes
139039
Stars and Bars Combinatorics Problem
23322
Combinatorics Inclusion - Exclusion Principle
73850
Cardinality of set of functions
114262
Find the cardinality of the following set $S_n=\{(x,y)|x^2+y^2=n, \text{where }x,y,n \in \mathbb Z\text{ and }n\geq0 \}$
11967
number of subsets of even and odd
35648
How many permutations of the set n={1,2,3,3,3,4,4,5} are possible without any consecutive identical elements?
132605
Finding the number of subsets of a set such that an element divides the succeeding element.
148796
Calculating $\tau(n)$, the number of positive divisors of $n \in \mathbb N$