Erdős Problem 1061 #
References:
- erdosproblems.com/1061
- [Gu04] Guy, Richard K., Unsolved problems in number theory. (2004), Problem B15.
@[reducible, inline]
Let S x count the number of ordered pairs of positive integers (a, b) with a + b ≤ x
such that σ(a) + σ(b) = σ(a + b), where σ is the sum of divisors function.
In particular, (a, b) and (b, a) are counted separately; an unordered variant could be obtained
by additionally requiring a ≤ b.
Equations
- One or more equations did not get rendered due to their size.
Instances For
How many (ordered) solutions are there to σ(a) + σ(b) = σ(a + b) with a + b ≤ x?
Is it true that this number is asymptotic to c * x for some constant c > 0?