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A211875 Primes of the form Phi(phi(k),3), the phi(k)-th Cyclotomic polynomial evaluated at 3, where phi is the Euler totient function. 1
2, 7, 61, 73, 6481, 530713, 42521761, 47763361, 23535794707, 282429005041, 374857981681, 150094634909578633, 13490012358249728401, 105919308797935444986721, 1076050302914923449767311155851656076154481 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..15.

MATHEMATICA

Union[Select[Cyclotomic[EulerPhi[#], x] /. x -> 3 & /@ Range[1000], PrimeQ]]

CROSSREFS

Sequence in context: A274600 A091687 A000892 * A065397 A255904 A046846

Adjacent sequences:  A211872 A211873 A211874 * A211876 A211877 A211878

KEYWORD

nonn

AUTHOR

Alexander Gruber, Feb 12 2013

STATUS

approved

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Last modified February 24 04:30 EST 2020. Contains 332197 sequences. (Running on oeis4.)