There is a pile with 15 coins on a table. At each step, Pedro choses one of the piles in the table with a>1 coins and divides it in two piles with b≥1 and c≥1 coins and writes in the board the product abc. He continues until there are 15 piles with 1 coin each. Determine all possible values that the final sum of the numbers in the board can have. ProductsOperationInvariantscono sur