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A004999 Sums of two nonnegative cubes. 12
0, 1, 2, 8, 9, 16, 27, 28, 35, 54, 64, 65, 72, 91, 125, 126, 128, 133, 152, 189, 216, 217, 224, 243, 250, 280, 341, 343, 344, 351, 370, 407, 432, 468, 512, 513, 520, 539, 559, 576, 637, 686, 728, 729, 730, 737, 756, 793, 854, 855, 945, 1000, 1001 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

LINKS

T. D. Noe, Table of n, a(n) for n = 1..1000

Kevin A. Broughan, Characterizing the Sum of Two Cubes, J. Integer Seqs., Vol. 6, 2003.

Index entries for sequences related to sums of cubes

MATHEMATICA

Union[(#[[1]]^3+#[[2]]^3)&/@Tuples[Range[0, 20], {2}]] (* Harvey P. Dale, Dec 04 2010 *)

PROG

(PARI) is(n)=my(k1=ceil((n-1/2)^(1/3)), k2=floor((4*n+1/2)^(1/3)), L); fordiv(n, d, if(d>=k1 && d<=k2 && denominator(L=(d^2-n/d)/3)==1 && issquare(d^2-4*L), return(1))); 0

list(lim)=my(v=List()); for(x=0, (lim+.5)^(1/3), for(y=0, min(x, (lim-x^3)^(1/3)), listput(v, x^3+y^3))); vecsort(Vec(v), , 8) \\ Charles R Greathouse IV, Jun 12 2012

(PARI) is(n)=my(L=sqrtnint(n-1, 3)+1, U=sqrtnint(4*n, 3)); fordiv(n, m, if(L<=m&m<=U, my(ell=(m^2-n/m)/3); if(denominator(ell)==1&&issquare(m^2-4*ell), return(1)))); 0 \\ Charles R Greathouse IV, Apr 16 2013

(Haskell)

a004999 n = a004999_list !! (n-1)

a004999_list = filter c2 [1..] where

   c2 x = any (== 1) $ map (a010057 . fromInteger) $

                       takeWhile (>= 0) $ map (x -) $ tail a000578_list

-- Reinhard Zumkeller, Dec 20 2013

CROSSREFS

Cf. A003325 (subsequence), subsequence of A045980.

Cf. A000578, A010057, A003325 (subsequence), subsequence of A045980.

Sequence in context: A056805 A226825 A046679 * A105125 A230314 A220263

Adjacent sequences:  A004996 A004997 A004998 * A005000 A005001 A005002

KEYWORD

nonn,easy,nice

AUTHOR

N. J. A. Sloane, Steven Finch

STATUS

approved

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Last modified November 23 22:48 EST 2014. Contains 249866 sequences.