TC RefactorableNumber


 * http://www.topcoder.com/stat?c=problem_statement&pm=6784

Summary
Given a subrange of integers between 1 and 2 million, determine which of them satisfy $$ \tau(n)|n$$, or in other words which numbers n are multiples of their divisor-count.

Note: this problem was solved in under 2 minutes by ACRush!

From TopCoder Single Round Match 343.

Hints

 * A variant of the Sieve of Eratosthenes is useful. See also here and the match commentary.