Zumkeller numbers | Rosetta Code | #22
URL to the problem page: http://rosettacode.org/wiki/Zumkeller_numbers Zumkeller numbers are the set of numbers whose divisors can be partitioned into two disjoint sets that sum to the same value. Each sum must contain divisor values that are not in the other sum, and all of the divisors must be in one or the other. There are no restrictions on how the divisors are partitioned, only that the two partition sums are equal. E.G. 6 is a Zumkeller number; The divisors {1 2 3 6} can be partitioned into two groups {1 2 3} and {6} that both sum to 6. 10 is not a Zumkeller number; The divisors {1 2 5 10} can not be partitioned into two groups in any way that will both sum to the same value. 12 is a Zumkeller number; The divisors {1 2 3 4 6 12} can be partitioned into two groups {1 3 4 6} and {2 12} that both sum to 14. Even Zumkeller numbers are common; odd Zumkeller numbers are much less so. For values below 10^6, there is at least one Zumkeller number in every...
