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A061075 Greatest prime number p(n) with decimal fraction period of length n. 8
3, 11, 37, 101, 271, 13, 4649, 137, 333667, 9091, 513239, 9901, 265371653, 909091, 2906161, 5882353, 5363222357, 52579, 1111111111111111111, 27961, 10838689, 8779, 11111111111111111111111, 99990001, 182521213001, 1058313049 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
LINKS
FORMULA
a(n) = A006530(A019328(n)). - Ray Chandler, May 10 2017
EXAMPLE
1/271 = 0.0036900369, period of n=5 for p(5)=271.
MATHEMATICA
a[n_] := Cyclotomic[n, 10] // FactorInteger // Last // First; Table[a[n], {n, 1, 26}] (* Jean-François Alcover, Aug 05 2013, after Pari *)
PROG
(PARI) a(n) = my(p); if(n<1, 0, p=factor(polcyclo(n, 10))[, 1]; p[#p])
CROSSREFS
Sequence in context: A007138 A046107 A243110 * A005422 A040017 A007615
KEYWORD
nonn,nice,base
AUTHOR
Heiner Muller-Merbach (hmm(AT)sozwi.uni-kl.de), May 29 2001
EXTENSIONS
Terms to a(322) in b-file from Ray Chandler, Apr 28 2017
a(323)-a(352) in b-file from Max Alekseyev, Apr 26 2022
STATUS
approved

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Last modified June 18 18:14 EDT 2024. Contains 373486 sequences. (Running on oeis4.)