--- Lélio Ribeiro de Paula <leliorp@...> wrote:
> How does pfgw evaluates phi(x,y)?

By multiplication and division of Phi(d,y) terms for d|x.

> I found this number to be a PrP, but can't write it in a more
> palatable way:
>
> phi(30,2^4200+13) is Fermat and Lucas PRP! (72.3111s+0.0435s)

There is no more palatable way. It's both succinct and clear,
and you can't ask for more than that.

Phil

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