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A057903 Positive integers that are not the sum of exactly two positive cubes. 2
1, 3, 4, 5, 6, 7, 8, 10, 11, 12, 13, 14, 15, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 29, 30, 31, 32, 33, 34, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 66, 67, 68, 69, 70, 71, 73, 74, 75, 76, 77, 78, 79 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Includes the cubes themselves (since a^3 = b^3 + c^3 has no solution, by the exponent 3 case of Fermat's Last Theorem), so is different from A022555.

LINKS

Table of n, a(n) for n=1..71.

Eric Weisstein's World of Mathematics, Cubic number.

FORMULA

Equals A022555 union A000578 - {0}.

MATHEMATICA

pr[n_] := Select[ PowersRepresentations[n, 2, 3], FreeQ[#, 0]& ]; Select[ Range[80], pr[#] == {} &] (* Jean-Fran├žois Alcover, Nov 08 2012 *)

CROSSREFS

Cf. A022555, A000578.

Sequence in context: A183296 A138928 A116587 * A247833 A047310 A184530

Adjacent sequences:  A057900 A057901 A057902 * A057904 A057905 A057906

KEYWORD

nonn

AUTHOR

Eric W. Weisstein

EXTENSIONS

Edited by N. J. A. Sloane, Sep 28 2007

STATUS

approved

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Last modified October 19 16:17 EDT 2019. Contains 328223 sequences. (Running on oeis4.)