A066890 Cubes that are the sum of three distinct positive cubes.

216, 729, 1728, 5832, 6859, 8000, 13824, 15625, 19683, 21952, 24389, 27000, 46656, 54872, 64000, 68921, 74088, 85184, 91125, 97336, 110592, 125000, 148877, 157464, 175616, 185193, 195112, 216000, 250047, 287496, 300763, 328509, 343000, 357911, 373248, 421875

Offset

1,1

References

David Wells, The Penguin Dictionary of Curious and Interesting Numbers (Rev. ed. 1997), pp. 130, 147.

Links

Donovan Johnson, Table of n, a(n) for n = 1..1000

Formula

a(n) = (A023042(n))^3. - Christian N. K. Anderson, Aug 10 2014

Example

729 is included because it is 9^3 and 1^3 + 6^3 + 8^3 = 729.

Mathematica

maxCube = (m = 67)^3; Reap[ Do[ bmax = (maxCube - a^3)^(1/3) // Ceiling; Do[ cmax = (maxCube - b^3)^(1/3) // Ceiling; Do[ n = a^3 + b^3 + c^3; If[n <= maxCube, If[ IntegerQ[n^(1/3)], Sow[n]]], {c, b, cmax}], {b, a, bmax}], {a, 1, (maxCube - 2)^(1/3) // Ceiling}]][[2, 1]] // Flatten // Union (* Jean-François Alcover, Mar 07 2013 *)

Crossrefs

Sequence in context: A208089 A333316 A275154 * A242296 A223507 A135590

Adjacent sequences: A066887 A066888 A066889 * A066891 A066892 A066893

Keyword

nonn

Author

Harvey P. Dale, Jan 22 2002

Extensions

Offset corrected by Arkadiusz Wesolowski, Aug 06 2012

Status

approved