A001239 - OEIS

A001239

Numbers that are the sum of 3 nonnegative cubes in more than 1 way.

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.

David Wells, The Penguin Dictionary of Curious and Interesting Numbers, Penguin Books, NY, 1986, p. 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 triples

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: A003998 A335544 A230400 * A184088 A348609 A205191

Adjacent sequences: A001236 A001237 A001238 * A001240 A001241 A001242

KEYWORD

nonn

AUTHOR

N. J. A. Sloane

STATUS

approved