phi(n),phi(n+1),phi(n+2) are equal

[wouter meeussen]

no other solutions n<4*10^6

W.


Select[Range[1000000], EulerPhi[#] === EulerPhi[# + 1] === EulerPhi[# + 2] &]
{5186}
Select[Range[1000000, 2000000],
  EulerPhi[#] === EulerPhi[# + 1] === EulerPhi[# + 2] &]
{}
Select[Range[2000000, 3000000],
  EulerPhi[#] === EulerPhi[# + 1] === EulerPhi[# + 2] &]
{}
Select[Range[3000000, 4000000],
    EulerPhi[#] === EulerPhi[# + 1] === EulerPhi[# + 2] &] // Timing
{127.188 Second, {}}

----- Original Message -----
From: "Yuval Dekel" <dekelyuval at hotmail.com>
To: <seqfan at ext.jussieu.fr>
Sent: Saturday, August 30, 2003 3:01 PM
Subject: phi(n),phi(n+1),phi(n+2) are equal


> I searched a solution to the equation phi(n)=phi(n+1)=phi(n+2) in the range
> n<=300000
> and found only the solution n=5186 .
>
> Perhaps someone with a faster machine than mine can find more solutions in a
> wider range to insert this sequence into the OEIS ?
>
> See :
> http://www.research.att.com/projects/OEIS?Anum=A001274
>
> Thanks,
> Yuval
>
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