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A008917 Numbers that are the sum of 3 positive cubes in more than one way. 10
251, 1009, 1366, 1457, 1459, 1520, 1730, 1737, 1756, 1763, 1793, 1854, 1945, 2008, 2072, 2241, 2414, 2456, 2458, 2729, 2736, 3060, 3391, 3457, 3592, 3599, 3655, 3745, 3926, 4105, 4112, 4131, 4168, 4229, 4320, 4376, 4402, 4437, 4447 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Of course reordering the terms does not count.

A025456(a(n)) > 1. [Reinhard Zumkeller, Apr 23 2009]

LINKS

T. D. Noe and Christian N. K. Anderson, Table of n, a(n) for n = 1..10000 (first 1000 terms are from T. D. Noe)

Christian N. K. Anderson, Decomposition of first 10,000 terms into multiple cube triples.

EXAMPLE

a(2) = 1009 = 1^3+2^3+10^3 = 4^3+6^3+9^3.

MATHEMATICA

Select[Range[4450], 1 < Length @ Cases[PowersRepresentations[#, 3, 3], {_?Positive, _?Positive, _?Positive}] &]  (* Jean-Fran├žois Alcover, Apr 04 2011 *)

PROG

(PARI) is(n)=k=ceil((n-2)^(1/3)); d=0; for(a=1, k, for(b=a, k, for(c=b, k, if(a^3+b^3+c^3==n, d++)))); d

n=3; while(n<5000, if(is(n)>1, print1(n, ", ")); n++) \\ Derek Orr, Aug 27 2015

CROSSREFS

Sequence in context: A179231 A108833 A228672 * A025396 A185941 A215607

Adjacent sequences:  A008914 A008915 A008916 * A008918 A008919 A008920

KEYWORD

nonn,easy,nice

AUTHOR

N. J. A. Sloane and J. H. Conway

STATUS

approved

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Last modified October 22 12:30 EDT 2019. Contains 328318 sequences. (Running on oeis4.)