The number of 1’s that are in the same position in Num and Parity Mask
9560
How to count the number of set bits in a 32-bit integer?
155372
Find the number of permutations in $S_n$ containing fixed elements in one cycle
121960
How many numbers from $1$ to $2^n$ will have $``11"$ as substring in binary representation?
37873
Number of zero digits in factorials
117758
Number of zeroes at end of factorial
26343
Number of certain (0,1)-matrices, Stanley's Enumerative Combinatorics
98313
Number of possible permutations of n1 1's, n2 2's, n3 3's, n4 4's such that no two adjacent elements are same?
136885
Series of natural numbers which has all same digits
41008
how many permutations of {1,2,...,9}
74839
Catalan numbers: bijection between applications of a binary operator and Dyck words.
148803
501 distinct coprime integers between 1 and 1000?
33161
Find the image of (1,1,1) by T
66784
Number of strings lenght $n$ with no consecutive zeros
98850
A positional number system for enumerating fixed-size subsets?
44745
How many positive integers less than 1000 have distinct digits and are even?
36486
Finding the total number of set-bits from 1 to n
60385
How to solve this sequence $165,195,255,285,345,x$