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A003998 Numbers that are a sum of distinct positive cubes in more than one way. 2
216, 217, 224, 225, 540, 559, 560, 567, 568, 728, 729, 736, 737, 756, 757, 764, 793, 801, 820, 828, 854, 855, 862, 863, 881, 882, 889, 890, 918, 919, 926, 927, 945, 946, 953, 954, 980, 981, 1008, 1009, 1036, 1044, 1045, 1071, 1072, 1073, 1079, 1080 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Zak Seidov and Robert Israel, Table of n, a(n) for n = 1..10000 (n = 1..1038 from Zak Seidov)

MAPLE

F:= proc(x, y) option remember;

  if y = 0 then 1

  elif y < x^3 then 0

  elif y = x^3 then 1

  else procname(x+1, y) + procname(x+1, y-x^3)

  fi

end proc:

select(t -> F(1, t) > 1, [$1..10000]); # Robert Israel, Dec 31 2015

MATHEMATICA

ok[n_] := Length[ Select[ Union[ Union /@ Flatten[ Table[ DeleteCases[ PowersRepresentations[n, k, 3], 0, 2], {k, 1, Floor[(n-1)^(1/3)]}], 1]], Total[#^3] == n & , 2]] == 2; Reap[ Do[ If[ ok[n], Print[n]; Sow[n]], {n, 1, 1100}]][[2, 1]](* Jean-Fran├žois Alcover, Feb 23 2012 *)

CROSSREFS

Cf. A001239.

Sequence in context: A192073 A176766 A018863 * A230400 A001239 A184088

Adjacent sequences:  A003995 A003996 A003997 * A003999 A004000 A004001

KEYWORD

nonn,easy,nice

AUTHOR

N. J. A. Sloane

EXTENSIONS

More terms from Larry Reeves (larryr(AT)acm.org), Mar 20 2000

STATUS

approved

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Last modified November 12 12:43 EST 2018. Contains 317109 sequences. (Running on oeis4.)