Applying the sum-of-digits operation to $4444^{4444}$ three times
853
Write down the sum of sum of  sum of digits of $4444^{4444}$
111602
Help with telescoping sum $\sum_{i=3}^n \frac{1}{i(i+3)} $
5037
Find the last two digits of $3^{45}$
72437
Sum of the digits of a perfect square
28957
Verifying that $2^{44}-1$ is divisible by $89$
105237
Alternating sum of binomial coefficients identity
122891
integer as sum of three binomials
157771
Nested exponent modulus, $2^{2^{517}} \pmod {23}$
20713
The sum of an uncountable number of positive numbers
108919
Numbers till 400 divisible by 2, 3, 5, 7
90068
Calculating the number of times a digit is written when given two numbers
91565
How to efficiently compute $\,25^{37}\pmod{55}$?
65802
The number of 5-digit numbers such that their sum of digits is even is?
51680
decimal representation of $2^m$ starts with a particular finite sequence of decimal digits
73020
Every integer is congruent to the sum of its digits mod 9
110975
Summation of reciprocals
14884
Compute a sum with partial fraction decomposition and generating functions