MathDB
SAMO 2011 Senior Round 3 Problem 3

Source:

September 7, 2011
number theoryleast common multiplemodular arithmetic

Problem Statement

We call a sequence of mm consecutive integers a friendly sequence if its first term is divisible by 11, the second by 22, ..., the (m1)th(m-1)^{th} by m1m-1, and in addition, the last term is divisible by m2m^2
Does a friendly sequence exist for (a) m=20m=20 and (b) m=11m=11?