Determine all positive integers M such that the sequence a0,a1,a2,⋯ defined by a_0 = M + \frac{1}{2} \qquad \textrm{and} \qquad a_{k+1} = a_k\lfloor a_k \rfloor \textrm{for} \, k = 0, 1, 2, \cdots contains at least one integer term. floor functionnumber theoryIMO ShortlistSequencesBritishMathematicalOlympiad