Difference Between Permutations Divisible by 9?
115145
Show that $n-m$ is a multiple of 9 when $n$ and $m$ have same digits
81822
How many integers between $1$ and $10^4$ contain exactly one $8$ and one $9$?
96585
Sums and permutation
127833
Proving that $7^n(3n+1)-1$ is divisible by 9
97254
What is the proof of permutations of similar objects?
83837
Odd/Even Permutations
11470
Divisibility of integers
38809
In how many ways can the letters of word $PERMUTATIONS$ be arranged if there are always 4 letters between P and S?
56229
On the difference between consecutive primes
140630
Permutations in JavaScript?
36182
Why doesn't the last digit method work for divisibility by 4?
34452
In how many ways can you choose $k$ numbers out of $\{1,2,3,\dots,n\}$ so none of them is consecutive?
86394
EVERGREEN string question. Combinations and permutations
112147
Proving $9$ divides $n^3 + (n+1)^3 + (n+2)^3$
117761
When is $\binom{n}{k}$ divisible by $n$?
153721
Conjugating a permutation
78946
Why does casting out $9$ and $11$ work to compute remainders?