A number or a short expression. Spacing and $ signs are ignored.
Solution
Note that the number of integers between 1 and 2012 that have n as a divisor is ⌊n2012⌋. Therefore, if we sum over the possible divisors, we see that the sum is equivalent to ∑d=12012⌊d2012⌋. This can be approximated by ∑d=12012d2012=2012∑d=12012d1≈2012ln(2012). As it turns out, 2012ln(2012)≈15300, which is worth 18 points. Using the very rough approximation ln(2012)≈7 still gives 14 points.
Want a route through all this instead of an archive? The track
puts 2,000 problems in a working order, from AMC 10 level to the IMO shortlist.
Source: Omni-MATH,
licensed Apache-2.0.
Statement and solution reproduced as published; topic and difficulty added by this site.