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A008850
Numbers n such that sum of divisors of n^2 is a cube.
4
1, 43098, 20746664124, 21531558370, 25933330155, 30519275171, 453393100534, 803844998180, 1233758294601, 2358796315843, 6260406046762, 7339897643091, 7540242750903, 8532869860592, 11879890160946, 17538398093508
OFFSET
1,2
REFERENCES
A. H. Beiler, Recreations in the Theory of Numbers, Dover, NY, 1964, p. 9.
L. E. Dickson, History of the Theory of Numbers. Carnegie Institute Public. 256, Washington, DC, Vol. 1, 1919; Vol. 2, 1920; Vol. 3, 1923, see vol. 1, p. 54.
Julian Havil, Gamma, Exploring Euler's Constant, Princeton University Press, Princeton and Oxford, 2003, page 92.
I. Kaplansky, The challenges of Fermat, Wallis and Ozanam (and several related challenges): II. Fermat's second challenge, Preprint, 2002.
LINKS
Donovan Johnson, 2252 terms > 9*10^11
Eric Weisstein's World of Mathematics, Fermat's Divisor Problem.
CROSSREFS
Cf. A008849.
Sequence in context: A256950 A237847 A236984 * A205733 A205914 A205906
KEYWORD
nonn,nice
EXTENSIONS
More terms from David W. Wilson (whose search was complete only through a(2) = 43098), Sep 15 1996
Kaplansky gives two further numbers with this property: 2597942466059820 and 6847610254216117540. The first is probably new and the second is in Dickson.
I. Kaplansky and Will Jagy have verified that there are no other terms below 9*10^11. - Oct 13 2002
STATUS
approved