how many n-digit palindromes exist
50238
How to calculate the number of palindromes of a given number of characters?
119031
How many 6 digit numbers are possible with no digit appearing more than thrice?
131863
Permutation question on alphabets
40763
Possible orders of permutations of $11$ symbols
21660
Check if string is palindrome in objective c
62577
The number of ways to order 26 alphabet letters, no two vowels occurring consecutively
60915
Count number of 1's in binary representation
96260
Number of occurrences of k consecutive 1's in a binary string of length n (containing only 1's and 0's)
80744
What is the number of strings at size $n$ that is constructed from ${a,b,c,d}$ and there is an even num of $a$
70756
python: recursive check to determine whether string is a palindrome
107027
Number of combinations and permutations of letters
136885
Series of natural numbers which has all same digits
145255
Fibonacci, tribonacci and other similar sequences
101719
Finding the n-th lexicographic permutation of a string
24422
Check string for palindrome
42706
How many $N$ digits binary numbers can be formed where $0$ is not repeated
74839
Catalan numbers: bijection between applications of a binary operator and Dyck words.