Congruence and Uniqueness of Certain Markoff Numbers
arXiv:math/0612620 · doi:10.4064/aa128-3-7
Abstract
By making use of only simple facts about congruence, we first show that every even Markoff number is congruent to 2 modulo 32, and then, generalizing an earlier result of Baragar, establish the uniqueness for those Markoff numbers c where one of 3c - 2 and 3c + 2 is a prime power, 4 times a prime power, or 8 times a prime power.
6 pages. In version 2: typos corrected, sections 3 and 4 combined as the new section 3