

A153635


Primes of the form 4x^3 + 27y^2, with x positive or negative.


2



23, 31, 59, 139, 211, 239, 283, 419, 491, 499, 563, 643, 743, 751, 823, 1291, 1319, 1327, 1399, 1427, 1579, 1823, 1931, 2039, 2687, 2767, 3011, 3119, 3163, 3191, 3271, 3299, 3307, 3371, 3559, 3767, 3803, 3919, 4027, 4091, 4099, 4243, 4423, 4567, 4639
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OFFSET

1,1


COMMENTS

Hardy and Wright: If there are an infinite number of these primes, then there are infinitely many cubic polynomials with integer coefficients and prime discriminant. It would also resolve the open conjecture that there are infinitely many nonisomorphic elliptic curves defined over the rationals and having prime conductor.
Union of A153636 and A154291.  T. D. Noe, Jan 06 2009
Several numbers are formed in more than one way, e.g. 23, 31, 239, 499, 2687, 3299, 4027, 5323, 6079, ..., .  Robert G. Wilson v, Feb 17 2009
All terms have been checked using Sage. See A154291 for more details.
Granville: "The most desired open problem in [asymptotic sieves] is to show that 4a^3 + 27b^2 is prime for infinitely many pairs of integers a, b (this is of interest because if 4a^3 + 27b^2 is prime then it is usually the conductor of the elliptic curve y^2 = x^3 + ax + b)."  Charles R Greathouse IV, Jun 06 2013


REFERENCES

G. H. Hardy and E. M. Wright, An Introduction to the Theory of Numbers, 6th Edition, Oxford Univ. Press, 2008, p. 595.


LINKS

Table of n, a(n) for n=1..45.
Andrew Granville, Different approaches to the distribution of primes, Milan Journal of Mathematics 78 (2009), pp. 125.


EXAMPLE

1427 = 4*(694)^3 + 27*7037^2. (* Robert G. Wilson v, Feb 17 2009 *)


MATHEMATICA

lst = {}; Do[ If[ z = 4x^3 + 27y^2; 0 < z < 10000 && PrimeQ@z, AppendTo[lst, z]; Print[{z, x, y}]], {y, 25000}, {x, Floor[(27 y^2/4)^(1/3)], Floor[(27 y^2/4)^(1/3)] + 100}]; Take[ Union@ lst, 45] (* Robert G. Wilson v, Feb 17 2009 *)


CROSSREFS

Cf. A153636 (positive x only).
Sequence in context: A030680 A330162 A006203 * A052160 A165985 A093014
Adjacent sequences: A153632 A153633 A153634 * A153636 A153637 A153638


KEYWORD

nonn


AUTHOR

T. D. Noe, Dec 29 2008, Jan 06 2009


EXTENSIONS

a(23)a(45) from Robert G. Wilson v, Feb 17 2009
Comment corrected by T. D. Noe, Jun 18 2009


STATUS

approved



