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A001239 Numbers that are the sum of 3 nonnegative cubes in more than 1 way. 3
216, 251, 344, 729, 855, 1009, 1072, 1366, 1457, 1459, 1520, 1674, 1728, 1729, 1730, 1737, 1756, 1763, 1793, 1854, 1945, 2008, 2072, 2241, 2414, 2456, 2458, 2729, 2736, 2752, 3060, 3391, 3402, 3457, 3500, 3592, 3599, 3655, 3744, 3745 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

REFERENCES

G. H. Hardy, Ramanujan, Cambridge Univ. Press, 1940, p. 12.

D. Wells, The Penguin Dictionary of Curious and Interesting Numbers. Penguin Books, NY, 1986, 165.

LINKS

Christian N. K. Anderson, Table of n, a(n) for n = 1..10000

Christian N. K. Anderson, Decomposition of first 10000 terms into cube triplets

MATHEMATICA

Select[Range[4000], Length[PowersRepresentations[#, 3, 3]] > 1 &] (* Harvey P. Dale, Feb 03 2011 *)

PROG

(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

CROSSREFS

Cf. A001235, A003998, A008917, A025396, A025456, A025447.

Sequence in context: A018863 A003998 A230400 * A184088 A205191 A204650

Adjacent sequences:  A001236 A001237 A001238 * A001240 A001241 A001242

KEYWORD

nonn

AUTHOR

N. J. A. Sloane.

STATUS

approved

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Last modified July 20 20:57 EDT 2017. Contains 289629 sequences.