In this post we denote the product of distinct primes dividing an integer $k> 1$ as $\operatorname{rad}(k)$, with the definition $\operatorname{rad}(1)=1$, that is the so-called radical of an integer, see this Wikipedia.
A well-known unsolved problem in number theory is related about the so-called amicable pairs. In this post I wanted to do a variation of this old problem and I wondered what should be a first statement or a reasonable conjecture about my sequence.
Definition. I define a the sequence of integers $n\geq 1$, and their correspondings integers $m\geq 1$ to be pairs of $\operatorname{rad}$-amicable numbers if these satisfy (both) the equations $$\sigma(n)=n+\operatorname{rad}(m)$$ and $$\sigma(m)=m+\operatorname{rad}(n),$$ where $\sigma(k)=\sum_{d\mid k}d$ denote the sum of divisors function.
Example. One has that $(33,45)$ is the second $\operatorname{rad}$-amicable pair, satisying $$1+3+11+33=\sigma(33)=33+\operatorname{rad}(45)=33+3\cdot 5.$$
Question. I would like to know what can be a first statement about previous defined sequence of $\operatorname{rad}$-amicable numbers, having a good mathematical content or well a conjecture about this sequence of integers $n\geq 1$ or pairs $(n,m)$. Many thanks.
Thus we evoke the scenario that this sequence is interesting and we need to explore with mathematics a first statement or conjecture related to our sequence. What should be a first step in the study of our sequence?
Computational fact. Our sequence of integers $n$ starts as $$6,33,45,46,52,1799,6625,\ldots$$ being thus the first few pairs $(n,m)$ these $(6,6),(33,45),(45,33),(46,52),(52,46),\ldots$
The following PARI/GP program searches efficiently for pairs doing the job but it is not guaranteed that all pairs are found.
The idea is : For every $s$ create all $u$ such that the radical of $u$ is $\sigma(s)-s$ and just verify whether this $u$ satisfies the other condition.
The program allows all exponents in $u$ to be upto $5$ (this can be changed). Upto $s=10^6$ , the following pairs were found :
All those pairs (and many additional pairs) occur upto $2\cdot 10^7$ with limit exponent $2$ :