Largest prime p such that phi^n(p) = 2, where phi^n means n iterations of Euler's totient function.

A136041

Largest prime p such that phi^n(p) = 2, where phi^n means n iterations of Euler's totient function.

Terms

    a(0) =3a(1) =7a(2) =19a(3) =43a(4) =163a(5) =487a(6) =1459a(7) =3079a(8) =8803a(9) =39367a(10) =78787a(11) =196831a(12) =581743a(13) =2125819a(14) =6381667a(15) =19131877a(16) =86093443a(17) =258280327a(18) =516560659a(19) =1214874127

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