Finding the number of arrangements of $n$ binary elements ($a$, $b$) with a maximum of $k$ repeating consecutive elements of one type
96260
Number of occurrences of k consecutive 1's in a binary string of length n (containing only 1's and 0's)
26569
Counting binary operations on a set with $n$ elements
146098
Number of nonempty subsets of a set with $n$ elements
17371
Recurrence relation for number of ternary strings that contain two consecutive zeros
27840
What about $[n,k,7]$ binary perfect code? (Exercise from the book Fundamentals of Error Correcting Codes)
158708
Counting the adjacent swaps required to convert one permutation into another
85023
Permutation of n objects with restriction of adjacent pairs
8458
Combinatorics problem based on Ferrers graph
107964
Simple combinatorics problem.
96086
Double Factorial: Number of possibilities to partition a set of $2n$ items into $n$ pairs
107010
How many elements of order $k$ are in $S_n$?
34452
In how many ways can you choose $k$ numbers out of $\{1,2,3,\dots,n\}$ so none of them is consecutive?
11998
In how many sequences of length $n$, the difference between every 2 adjacent elements is $1$ or $-1$?
100832
Number of binary trees with $N$ nodes
89611
Combinations of selecting $n$ objects with $k$ different types
48838
Proving the number of $n$ length binary strings with no consecutive $1's$ $b_n$ is equal to $b_{n-1} + b_{n-2}$
45448
Minimum number of $k$-partitions of a set of size $n$ to enumerate all $n \choose k$ combinations