OFFSET
1,1
EXAMPLE
3^3 + 5^3 = 152 = a(1).
3^3 + 7^3 = 370 = a(2).
5^3 + 7^3 = 468 = a(3).
MAPLE
A137632 := proc(amax) local a, p, q; a := {} ; p := 3 ; while p^3 < amax do q := nextprime(p) ; while p^3+q^3 < amax do a := a union {p^3+q^3} ; q := nextprime(q) ; od: p := nextprime(p) ; od: sort(convert(a, list)) ; end: A137632(80000) ; # R. J. Mathar, May 04 2008
MATHEMATICA
f[upto_]:=Module[{max=Ceiling[Power[upto-27, (3)^-1]], prs}, prs=Prime[Range[2, max]]; Select[Union[Total/@(Subsets[prs, {2}]^3)], #<=upto&]]; f[31000] (* Harvey P. Dale, Apr 20 2011 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
M. F. Hasler, Apr 13 2008
EXTENSIONS
More terms from R. J. Mathar, Apr 13 2008, May 04 2008
STATUS
approved