

A134738


Cubes which are not the sum of three squares.


4



343, 3375, 12167, 21952, 29791, 59319, 103823, 166375, 216000, 250047, 357911, 493039, 658503, 778688, 857375, 1092727, 1367631, 1404928, 1685159, 1906624, 2048383, 2460375, 2924207, 3442951, 3796416, 4019679, 4657463, 5359375
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OFFSET

1,1


COMMENTS

This sequence was inspired by email from Ray Chandler, Nov 07 2007


LINKS

Robert Israel, Table of n, a(n) for n = 1..10000


FORMULA

a(n) = A004215(n)^3. [From Ray Chandler, Jan 29 2009]


MAPLE

N:= 10^10: # to get all terms <= N
sort([seq(seq(4^(3*i) * (8*j + 7)^3, j = 0 .. floor((N^(1/3)/4^i  7)/8)), i = 0 .. floor(log[4](N^(1/3))))]); # Robert Israel, Dec 26 2017


MATHEMATICA

b = Table[x^3, {x, 1, 300}]; a = {}; Do[Do[Do[AppendTo[a, (x^2 + y^2 + z^2)^3], {x, 0, 30}], {y, 0, 30}], {z, 0, 30}]; Union[a]; Complement[b, a] (*Artur Jasinski*)
Select[Range[200]^3, SquaresR[3, #]==0&] (* Harvey P. Dale, Feb 03 2015 *)


CROSSREFS

Cf. A004215, A134739.
Sequence in context: A016923 A016983 A267321 * A017151 A017247 A017355
Adjacent sequences: A134735 A134736 A134737 * A134739 A134740 A134741


KEYWORD

nonn


AUTHOR

Artur Jasinski, Nov 07 2007


EXTENSIONS

Extended by Ray Chandler, Jan 29 2009


STATUS

approved



