OFFSET
1,1
LINKS
Chai Wah Wu, Table of n, a(n) for n = 1..10000
FORMULA
{k >0: k^2 in A024975}. [R. J. Mathar, Oct 06 2009]
EXAMPLE
6 is in the sequence because 6^2 = 1^3+2^3+3^3.
15 is in the sequence because 15^2 = 1^3+2^3+6^3.
MAPLE
N:= 1000: # to get all terms <= N
sc:= {seq(seq(seq(a^3 + b^3 + c^3, a = 1 .. min(b-1, floor((N^2 - b^3 - c^3)^(1/3)))), b = 2 .. min(c-1, floor((N^2 - c^3)^(1/3)))), c = 3 .. floor(N^(2/3)))}:
select(t -> member(t^2, sc), [$1..N]); # Robert Israel, Jan 27 2015
MATHEMATICA
lst={}; Do[Do[Do[d=Sqrt[a^3+b^3+c^3]; If[d<=834&&IntegerQ[d], AppendTo[lst, d]], {c, b+1, 5!, 1}], {b, a+1, 5!, 1}], {a, 5!}]; Take[Union@lst, 123]
Sqrt[# ]&/@Select[Total/@Subsets[Range[50]^3, {3}], IntegerQ[Sqrt[#]]&]// Union (* Harvey P. Dale, Oct 14 2020 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Vladimir Joseph Stephan Orlovsky, Sep 20 2009
EXTENSIONS
Comments moved to the examples by R. J. Mathar, Oct 07 2009
Title corrected by Jeppe Stig Nielsen, Jan 26 2015
STATUS
approved