Definition:Amicable Triplet/Definition 2

Definition
Let $m_1, m_2, m_3 \in \Z_{>0}$ be (strictly) positive integers. $\left({m_1, m_2, m_3}\right)$ are an amicable triplet :
 * $\sigma \left({m_1}\right) = \sigma \left({m_2}\right) = \sigma \left({m_3}\right) = m_1 + m_2 + m_3$

where $\sigma \left({m}\right)$ denotes the $\sigma$ function.

Also see

 * Equivalence of Definitions of Amicable Triplet