MathDB
find 3 consecutive positive integers given 5 conditions

Source: JBMO Shortlist 2014 NT6

April 24, 2019
number theoryconsecutivepositive integerssquarefreedecimal representation

Problem Statement

Vukasin, Dimitrije, Dusan, Stefan and Filip asked their teacher to guess three consecutive positive integers, after these true statements: Vukasin: " The sum of the digits of one number is prime number. The sum of the digits of another of the other two is, an even perfect number.(nn is perfect if σ(n)=2n\sigma\left(n\right)=2n). The sum of the digits of the third number equals to the number of it's positive divisors". Dimitrije:"Everyone of those three numbers has at most two digits equal to 11 in their decimal representation". Dusan:"If we add 1111 to exactly one of them, then we have a perfect square of an integer" Stefan:"Everyone of them has exactly one prime divisor less than 1010". Filip:"The three numbers are square free". Professor found the right answer. Which numbers did he mention?