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A177918 Numbers k such that k^3 divides 18^(k^2) - 1. 15
1, 17, 343927, 1414961, 28626075991, 610559655569, 5417488064959 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
COMMENTS
17 divides a(n) for n > 1.
LINKS
MATHEMATICA
Select[Range[350000], Mod[PowerMod[18, #^2, #^3] - 1, #^3] == 0 &] (* Julien Kluge, Sep 20 2016 *)
CROSSREFS
Cf. A128358 (k divides 18^k - 1), A128398 (k^2 divides 18^k - 1).
Sequence in context: A203677 A099499 A051157 * A297488 A177816 A130653
KEYWORD
hard,more,nonn
AUTHOR
Alexander Adamchuk, May 14 2010
EXTENSIONS
Three more terms from Max Alekseyev, Oct 02 2010
STATUS
approved

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Last modified February 21 10:54 EST 2024. Contains 370233 sequences. (Running on oeis4.)