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A127263
Numbers k such that k^3 divides 2^(k^2)+1.
19
1, 3, 57, 32547, 9961491, 297381939, 1338104811, 3942759027, 5688011361, 8920514307, 9146532873, 40253706489, 243640690617, 764039295291, 1127102902923, 1556475424971, 2251315404417, 3005607686883, 5222670270483
OFFSET
1,2
COMMENTS
If k belongs to this sequence, then so does (2^(k^2)+1)/k^2.
From Alexander Adamchuk, May 14 2010: (Start)
3 divides a(n) for n>1.
19 divides a(n) for n>2. (End)
LINKS
MATHEMATICA
Select[Range[100000], Divisible[2^(#^2) + 1, #^3] &] (* Robert Price, Mar 23 2020 *)
KEYWORD
nonn
AUTHOR
Max Alekseyev, Mar 27 2007, Mar 29 2007, Apr 18 2007
EXTENSIONS
a(7) from Ryan Propper, Jan 01 2008
a(8)-a(19) from Max Alekseyev, May 14 2010
STATUS
approved