Recent content by ittalo25

Hi guys, my english is very bad but let me try translate the question: Let $ a_n=\frac{(n+9)!}{(n-1)!} $ . Let k the lesser natural number since that the first digit (on the right side) after all the zeros of $ a_k $ is odd. Example: $ a_k =$ 4230000000 or $ a_k =$ 62345000 This odd digit...