>> From: Aaron Meyerowitz "meyerowi"
>>> From: Carl Devore "devore"
>
>> >> From: "N. J. A. Sloane" "njas"
>>
>> Is this a known bug?
>> > with(numtheory);
>> > invphi(1610510);
>> []
>> > phi(1771561);
>> 1610510
>> In other words invphi(1610510); gave an incorrect answer.
>
>My investigation so far shows that this bug will occur for
>invphi((p-1)*p^n) for n>1 and p any of the primes
>11, 23, 29, 31, 47, 53, 59, 67, 71, 79, 83, 89, 103, 107, 113, 131, ....
I.E. for phi(p^(n+1))
The code looks very "cute" but quite opaque. Other packages seem to find
invphi
correctly and MUCH more quickly. The problem goes back at least to Maple VR5.
Has it really never been noticed before?
|
(NAG)
