Consecutive Integers with Same Euler Phi Value/Examples/15

From ProofWiki
Jump to navigation Jump to search

Example of Consecutive Integers with Same Euler Phi Value

Let $\phi: \Z_{>0} \to \Z_{>0}$ denote the Euler $\phi$ function: the number of strictly positive integers less than or equal to $n$ which are prime to $n$.

Then:

$\map \phi {15} = \map \phi {16} = 8$


Proof

From $\phi$ of $15$:

$\map \phi {15} = 8$

From the corollary to Euler Phi Function of Prime Power:

$\map \phi {16} = \map \phi {2^4} = 2^{4 - 1} = 8$

Hence the result.

$\blacksquare$