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A061564 Numbers k such that the repeating part of the decimal expansion of 1/k (omitting leading or trailing zeros) forms a prime number. 1
3, 12, 18, 27, 30, 33, 36, 45, 48, 75, 120, 180, 192, 198, 270, 288, 300, 330, 333, 360, 369, 450, 480, 495, 750, 768, 909, 1152, 1200, 1584, 1800, 1875, 1920, 1980, 1998, 2151, 2304, 2439, 2700, 2880, 2997, 3000, 3072, 3300, 3330, 3333, 3600, 3690, 4500, 4800 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
LINKS
EXAMPLE
1/18 = 0.05555555..., the repeating part is 5, so 18 is in the sequence.
277 is not a term because the repetend of 1/277 is 3610108303249097472924187725631768953068592057761732851985559566787, which is not a prime. - Barry Smyth, Mar 31 2022
CROSSREFS
Sequence in context: A125821 A239052 A063229 * A348169 A342785 A166038
KEYWORD
easy,nonn,base
AUTHOR
Brian Wallace (wallacebrianedward(AT)yahoo.co.uk), May 18 2001
EXTENSIONS
Corrected and extended by Klaus Brockhaus, May 19 2001
More terms from Lior Manor, Nov 26 2001
Incorrect term 277 removed by Barry Smyth, Mar 31 2022
Corrected and extended by Sean A. Irvine, Feb 25 2023
STATUS
approved

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Last modified April 20 12:09 EDT 2024. Contains 371838 sequences. (Running on oeis4.)