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A128684
Numbers k such that k^3 divides 11^(k^2) + 1.
20
1, 3, 111, 24753, 1770231, 23401797, 39402669, 65498547, 298100379, 440377293, 1788478509, 5218600731, 8786795187, 14606175981, 24342867543, 45340639419, 98204136339, 5032808252679, 5293823142513, 6241891310439, 7013907181779
OFFSET
1,2
COMMENTS
3 divides a(n) for n > 1.
MATHEMATICA
Select[Range[5*10^6], Mod[ 11^(#^2)+1, #^3]==0 &] (* G. C. Greubel, Jan 18 2018 *)
KEYWORD
nonn
AUTHOR
Alexander Adamchuk, Mar 31 2007
EXTENSIONS
a(5) from J. Mulder (jasper.mulder(AT)planet.nl), Jan 26 2010
Terms from a(6) onward from Max Alekseyev, May 14 2010
STATUS
approved