A232703 Numbers k that divide sigma(k) + sigma(k^2).

1, 2, 185, 113125, 535350201, 71373089217, 82225037115, 156231750533, 268821356379

Offset

1,2

Comments

a(10) > 10^12. - Giovanni Resta, Jun 10 2016

Links

Table of n, a(n) for n=1..9.

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).

Cf. A232547, A065764, A247222.

Sequence in context: A094483 A258426 A163794 * A135126 A053936 A252765

Adjacent sequences: A232700 A232701 A232702 * A232704 A232705 A232706

Keyword

nonn,hard,more

Author

Alex Ratushnyak, Nov 28 2013

Extensions

a(6)-a(9) from Giovanni Resta, Jun 10 2016

Status

approved