%I #31 May 21 2022 13:59:22
%S 216,251,344,729,855,1009,1072,1366,1457,1459,1520,1674,1728,1729,
%T 1730,1737,1756,1763,1793,1854,1945,2008,2072,2241,2414,2456,2458,
%U 2729,2736,2752,3060,3391,3402,3457,3500,3592,3599,3655,3744,3745
%N Numbers that are the sum of 3 nonnegative cubes in more than 1 way.
%D G. H. Hardy, Ramanujan, Cambridge Univ. Press, 1940, p. 12.
%D David Wells, The Penguin Dictionary of Curious and Interesting Numbers, Penguin Books, NY, 1986, p. 165.
%H Christian N. K. Anderson, <a href="/A001239/b001239.txt">Table of n, a(n) for n = 1..10000</a>
%H Christian N. K. Anderson, <a href="/A001239/a001239.txt">Decomposition</a> of first 10000 terms into cube triples
%t Select[Range[4000], Length[PowersRepresentations[#, 3, 3]] > 1 &] (* _Harvey P. Dale_, Feb 03 2011 *)
%o (PARI) is(n)=my(t); for(a=0, sqrtnint(n, 3), my(a3=a^3, c); for(b=0, min(a, sqrtnint(n-a3, 3)), if(ispower(n-a3-b^3, 3, &c) && c <= b && t++>1, return(1)))); 0 \\ _Charles R Greathouse IV_, Jul 02 2017
%Y Cf. A001235, A003998, A008917, A025396, A025456, A025447.
%K nonn
%O 1,1
%A _N. J. A. Sloane_
|