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A199191 Numbers k such that 3^(2k-3) + 3^(k-1) + 1 is prime. 2
2, 3, 4, 5, 6, 10, 11, 41, 83, 160, 178, 526, 881, 2578, 3772, 11873 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
Numbers k such that A198410(k) is prime.
LINKS
MATHEMATICA
Select[Range[250], PrimeQ[((3^(#-1) + 1)^3 -1)/3^#]&]
CROSSREFS
Sequence in context: A212774 A131934 A066501 * A102570 A113007 A113325
KEYWORD
nonn,hard,more
AUTHOR
Michel Lagneau, Nov 03 2011
EXTENSIONS
a(16) from Michael S. Branicky, May 12 2023
STATUS
approved

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Last modified March 28 05:39 EDT 2024. Contains 371235 sequences. (Running on oeis4.)