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A109887
Numbers k such that 3^k + phi(k) is prime.
1
3, 4, 10, 20, 44, 60, 583, 677, 947, 1182, 12048, 16018, 74316
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OFFSET
1,1
COMMENTS
All terms correspond to certified primes (Primo 2.2.0 beta). No more terms through 10000.
a(14) > 10^5. - Donovan Johnson, Feb 06 2010
LINKS
Table of n, a(n) for n=1..13.
MATHEMATICA
Do[If[PrimeQ[3^n + EulerPhi[n]], Print[n]], {n, 1, 10000}]
CROSSREFS
Cf. A000010 (phi), A109889.
Sequence in context: A326832 A357812 A321197 * A200981 A266729 A103038
Adjacent sequences: A109884 A109885 A109886 * A109888 A109889 A109890
KEYWORD
nonn,hard,more
AUTHOR
Ryan Propper, Aug 31 2005
EXTENSIONS
a(11)-a(13) from Donovan Johnson, Feb 06 2010
STATUS
approved

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Last modified May 21 17:14 EDT 2026. Contains 395799 sequences.
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