A022555 Positive integers that are not the sum of two nonnegative cubes.

3, 4, 5, 6, 7, 10, 11, 12, 13, 14, 15, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 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, 66, 67, 68, 69, 70, 71, 73, 74, 75, 76, 77

Offset

1,1

Comments

Omits the positive cubes (A000578) since m^3 = 0^3 + m^3, so is different from A057903.

Links

T. D. Noe, Table of n, a(n) for n=1..10000

Index entries for sequences related to sums of cubes

Maple

read transforms; cub := series(add(q^(n^3), n=0..100), q, 1000001); t1 := series(cub^2, q, 2000); t2 := POWERS(t1, q, 2000); COMPl(t2);

Mathematica

r[n_] := Reduce[x >= 0 && y >= 0 && n == x^3 + y^3, {x, y}, Integers]; Select[ Range[80], r[#] === False &]  (* Jean-François Alcover, Nov 06 2012 *)
Select[Range@100, PowersRepresentations[#, 2, 3]=={}&] (* A much faster solution given by Giovanni Resta, Nov 06 2012 *)

Crossrefs

Complement of A004999. Cf. A004825, A022561, A022566, A057903, A000578.

Sequence in context: A226116 A128659 A364083 * A047308 A092860 A351392

Adjacent sequences: A022552 A022553 A022554 * A022556 A022557 A022558

Keyword

nonn

Author

N. J. A. Sloane.

Extensions

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

Status

approved