Granville number

In mathematics, specifically number theory, Granville numbers are an extension of the perfect numbers.

In 1996, Andrew Granville proposed the following construction of the set ${\displaystyle {\mathcal {S}}}$:

A Granville number is an element of ${\displaystyle {\mathcal {S}}}$ for which equality holds i.e. it is equal to the sum of its proper divisors that are also in ${\displaystyle {\mathcal {S}}}$. Granville numbers are also called ${\displaystyle {\mathcal {S}}}$-perfect numbers.

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