The Erdős–Moser equation -------------------------
Consider the following equation: 1*k + 2k +… + (m – 1)k = mk where m and k* are integers.
The only known solution is 11 + 21 = 31.
In the 1950s, Erdős conjectured that there were no others.
Many results have been obtained concerning k and m under the assumption that the equation has at least one other solution. Here are a few of them in chronological order, beginning with one obtained by Leo Moser: