A290846 Numbers k such that sum of squares of divisors of k is a cube.

1, 4182, 4879, 122664360, 315870765, 4621320120, 5006430130, 20245909880, 220899101736, 239307360214, 812593845485

Offset

1,2

Comments

It is known that A006532 is an infinite sequence. Is this sequence infinite?

a(12) > 10^12. - Giovanni Resta, Aug 14 2017

Links

Table of n, a(n) for n=1..11.

Giovanni Resta, A list of 3110 terms > 10^12

Example

4879 is a term because 1^2 + 7^2 + 17^2 + 41^2 + 119^2 + 287^2 + 697^2 + 4879^2 = 290^3.

Prog

(PARI) isok(n) = ispower(sigma(n, 2), 3);

Crossrefs

Cf. A001157, A006532, A046655.

Sequence in context: A358555 A050937 A135953 * A236805 A202530 A242770

Adjacent sequences: A290843 A290844 A290845 * A290847 A290848 A290849

Keyword

nonn,more

Author

Altug Alkan, Aug 12 2017

Extensions

a(6)-a(11) from Giovanni Resta, Aug 14 2017

Status

approved