A020476 Numbers k such that the sum of divisors of k^3 is a cube.

1, 30154214043975990969, 76630991932799573643, 3590918978816938469301573291605, 68804810614900760202830061602802, 527113576787083306927808065765554478755087

Offset

1,2

Comments

WARNING: the listed terms are not proved to be in order. According to Basso (2017), it is not even proved that a(2) = 30154214043975990969. - Max Alekseyev, Mar 25 2023

Links

Table of n, a(n) for n=1..6.

Andrea Basso, Power values of the sigma function, Bachelor’s Project Mathematics, University of Gronigen, July 2017. See Appendix D p. 36.

Prog

(PARI) isok(n) = ispower(sigma(n^3), 3); \\ Michel Marcus, Jul 19 2017

Crossrefs

Cf. A000578, A175926.

Sequence in context: A132902 A288290 A219321 * A231562 A257370 A104283

Adjacent sequences: A020473 A020474 A020475 * A020477 A020478 A020479

Keyword

nonn,more

Author

David W. Wilson

Status

approved