Answer to June 2009 Problem
Missing Number Problem

William Jacob Bechem
Games Magazine March 2009

There are ten positive integers less than 1000 that cannot be written as the sum of consecutive natural numbers.
For example, 9 = 4 + 5, 10 = 1 + 2 + 3 + 4,
11 = 5 + 6, and 12 = 3 + 4 + 5.

The first two numbers that cannot be written as the sum of consecutive natural numbers are 1 and 2. Can you find the other eight exceptions?



Solution to the Problem:

The answer is all the powers of 2:
1, 2, 4, 8, 16, 32, 64, 128, 256, 512.


Correctly solved by:

1. John C. Funk Ventura, California
2. David & Judy Dixon Bennettsville, South Carolina
3. Richard K. Johnson La Jolla, California
4. Les Walker Ventura, California