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Printjmc
algebra intermediate
Problem
Say that an integer is yummy if there exist several consecutive integers, including , that add up to 2014. What is the smallest yummy integer?
Solution
Here is a sequence of consecutive integers that add up to : So is yummy.
Assume there is a yummy integer less than . Then there is a sequence of consecutive integers (including at least one less than ) that add up to . Let be the least integer in the sequence, so .
Because the sum of the sequence is nonnegative, it includes the numbers . Because the sum of the sequence is positive, besides the numbers above, it includes . But
So the sum of the sequence exceeds , which is a contradiction. Hence there is no yummy integer less than .
Therefore the least yummy integer is .
Assume there is a yummy integer less than . Then there is a sequence of consecutive integers (including at least one less than ) that add up to . Let be the least integer in the sequence, so .
Because the sum of the sequence is nonnegative, it includes the numbers . Because the sum of the sequence is positive, besides the numbers above, it includes . But
So the sum of the sequence exceeds , which is a contradiction. Hence there is no yummy integer less than .
Therefore the least yummy integer is .
Final answer
-2013