|
%I #29 Mar 25 2023 17:04:35
%S 1,30154214043975990969,76630991932799573643,
%T 3590918978816938469301573291605,68804810614900760202830061602802,
%U 527113576787083306927808065765554478755087
%N Numbers k such that the sum of divisors of k^3 is a cube.
%C 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
%H Andrea Basso, <a href="https://fse.studenttheses.ub.rug.nl/15363/1/BSc_Math_2017_Basso_A.pdf">Power values of the sigma function</a>, Bachelor’s Project Mathematics, University of Gronigen, July 2017. See Appendix D p. 36.
%o (PARI) isok(n) = ispower(sigma(n^3), 3); \\ _Michel Marcus_, Jul 19 2017
%Y Cf. A000578, A175926.
%K nonn,more
%O 1,2
%A _David W. Wilson_
| 