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A232703
Numbers k that divide sigma(k) + sigma(k^2).
3
1, 2, 185, 113125, 535350201, 71373089217, 82225037115, 156231750533, 268821356379
OFFSET
1,2
COMMENTS
a(10) > 10^12. - Giovanni Resta, Jun 10 2016
MATHEMATICA
Select[Range[150000], Mod[Plus @@ DivisorSigma[1, {#, #^2}], #] == 0 &] (* Giovanni Resta, Jun 10 2016 *)
CROSSREFS
Cf. A000203 (sigma(n) = sum of divisors of n).
Sequence in context: A094483 A258426 A163794 * A135126 A053936 A252765
KEYWORD
nonn,hard,more
AUTHOR
Alex Ratushnyak, Nov 28 2013
EXTENSIONS
a(6)-a(9) from Giovanni Resta, Jun 10 2016
STATUS
approved