cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A008850 Numbers n such that sum of divisors of n^2 is a cube.

This page as a plain text file.
%I A008850 #28 Feb 16 2025 08:32:32
%S A008850 1,43098,20746664124,21531558370,25933330155,30519275171,453393100534,
%T A008850 803844998180,1233758294601,2358796315843,6260406046762,7339897643091,
%U A008850 7540242750903,8532869860592,11879890160946,17538398093508
%N A008850 Numbers n such that sum of divisors of n^2 is a cube.
%D A008850 A. H. Beiler, Recreations in the Theory of Numbers, Dover, NY, 1964, p. 9.
%D A008850 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.
%D A008850 Julian Havil, Gamma, Exploring Euler's Constant, Princeton University Press, Princeton and Oxford, 2003, page 92.
%D A008850 I. Kaplansky, The challenges of Fermat, Wallis and Ozanam (and several related challenges): II. Fermat's second challenge, Preprint, 2002.
%H A008850 Donovan Johnson, <a href="/A008850/a008850.txt">2252 terms > 9*10^11</a>
%H A008850 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/FermatsDivisorProblem.html">Fermat's Divisor Problem.</a>
%Y A008850 Cf. A008849.
%K A008850 nonn,nice
%O A008850 1,2
%A A008850 _N. J. A. Sloane_
%E A008850 More terms from _David W. Wilson_ (whose search was complete only through a(2) = 43098), Sep 15 1996
%E A008850 Kaplansky gives two further numbers with this property: 2597942466059820 and 6847610254216117540. The first is probably new and the second is in Dickson.
%E A008850 I. Kaplansky and _Will Jagy_ have verified that there are no other terms below 9*10^11. - Oct 13 2002