A114070 sigma(n) + n is a cube.

13, 76, 280, 4258, 4719, 4887, 12207, 13106, 41823, 42804, 51671, 54261, 56283, 65512, 77671, 95139, 98219, 135724, 147440, 149176, 177911, 220546, 239599, 279145, 285347, 285957, 299432, 308503, 312137, 335106, 350739, 525429, 611123, 634600, 663377, 700064

Offset

1,1

Links

Table of n, a(n) for n=1..36.

Example

sigma(13) + 13 = 27 = 3^3.

Mathematica

Select[Range[701100], IntegerQ[Surd[DivisorSigma[1, #]+#, 3]]&] (* Harvey P. Dale, Oct 22 2023 *)

Prog

(PARI) isok(n) = ispower(sigma(n) + n, 3); \\ Michel Marcus, Jan 22 2014

Crossrefs

Cf. A155085.

Sequence in context: A103968 A073544 A051361 * A005340 A114244 A050485

Adjacent sequences: A114067 A114068 A114069 * A114071 A114072 A114073

Keyword

nonn

Author

Giovanni Resta, Feb 13 2006

Extensions

More terms from Michel Marcus, Jan 22 2014

Status

approved