Question 78
Determine all natural numbers $n$ such that for every positive divisor $d$ of $n$ we have
$$
d+1 \mid n+1
$$
$$
d+1 \mid n+1
$$
MathNet 2016-part-06 — 184 problems (EN–VI) Question 78
Math Olympiad Vault · MathNet 2016-part-06 — 184 problems (EN–VI)