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A007490
Primes of form x^3 + y^3 + z^3 where x,y,z > 0.
(Formerly M3036)
10
3, 17, 29, 43, 73, 127, 179, 197, 251, 277, 281, 307, 349, 359, 397, 433, 521, 547, 557, 577, 593, 701, 757, 811, 853, 857, 863, 881, 919, 953, 1009, 1051, 1091, 1217, 1249, 1367, 1459, 1483, 1559, 1583, 1637, 1753, 1801, 1861, 1907, 2017, 2027, 2069, 2087
OFFSET
1,1
COMMENTS
Heath-Brown shows that this sequence is infinite. - Charles R Greathouse IV, Jul 23 2009
The definition implies x, y, z > 0, so the representation (x=0, y=z=1) for the prime 2 or the representation (x=-4, y=-2, z=5) for the prime 53 are not admitted. - R. J. Mathar, Mar 19 2010
REFERENCES
W. SierpiƄski, A Selection of Problems in the Theory of Numbers. Macmillan, NY, 1964, p. 108.
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
LINKS
D. R. Heath-Brown, Primes represented by x^3 + 2y^3. Acta Mathematica 186 (2001), pp. 1-84.
R. G. Wilson, V, Note, n.d.
MATHEMATICA
nn = 3000; Select[Union[Flatten[Table[x^3 + y^3 + z^3, {x, nn^(1/3)}, {y, x, (nn - x^3)^(1/3)}, {z, y, (nn - x^3 - y^3)^(1/3)}]]], PrimeQ] (* T. D. Noe, Sep 18 2012 *)
PROG
(PARI) list(lim)=my(v=List(), k, t); lim\=1; for(x=1, sqrtnint(lim-2, 3), for(y=1, min(sqrtnint(lim-x^3-1, 3), x), k=x^3+y^3; for(z=1, min(sqrtnint(lim-k, 3), y), if(isprime(t=k+z^3), listput(v, t))))); Set(v) \\ Charles R Greathouse IV, Sep 14 2015
CROSSREFS
Cf. A003072 (all numbers).
Sequence in context: A249374 A106085 A172487 * A173587 A022887 A063715
KEYWORD
nonn
EXTENSIONS
More terms from Vladimir Joseph Stephan Orlovsky, Mar 18 2010
Definition clarified by Charles R Greathouse IV, Sep 14 2015
STATUS
approved