OFFSET
1,1
COMMENTS
Root values equal terms from sequence A000404 'Sum of 2 nonzero squares'.
In other words, a(n)=(A000404(n))^3. - Artur Jasinski, Nov 29 2007
Obviously, if n and m are different members of this sequence, then n*m is also a member of this sequence. Additionally, if k^3 is a member of this sequence and k is not in A050804, then k^6 is also a member of this sequence. - Altug Alkan, May 11 2016
REFERENCES
Ian Stewart, "Game, Set and Math", Chapter 8 'Close Encounters of the Fermat Kind', Penguin Books, Ed. 1991, pp. 107-124.
EXAMPLE
551368 or 82^3 = 82^2 + 738^2 = 242^2 + 702^2.
MATHEMATICA
a[n_]:=Module[{c=0}, i=1; While[i^2<n && c!=1, If[IntegerQ[Sqrt[n-i^2]], c=1]; i++]; c]; Select[Range[98]^3, a[#]==1&] (* Jayanta Basu, May 30 2013 *)
Select[Range[100]^3, Length[DeleteCases[PowersRepresentations[#, 2, 2], w_ /; MemberQ[w, 0]]] > 0 &] (* Michael De Vlieger, May 11 2016 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Patrick De Geest, Sep 15 1999
EXTENSIONS
Edited by N. J. A. Sloane, May 15 2008 at the suggestion of R. J. Mathar
STATUS
approved