

A022555


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


6



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
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OFFSET

1,1


COMMENTS

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


LINKS



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 &] (* JeanFrançois Alcover, Nov 06 2012 *)
Select[Range@100, PowersRepresentations[#, 2, 3]=={}&] (* A much faster solution given by Giovanni Resta, Nov 06 2012 *)


CROSSREFS



KEYWORD

nonn


AUTHOR



EXTENSIONS



STATUS

approved



