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A040028
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Primes p such that x^3 = 2 has a solution mod p.
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29
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2, 3, 5, 11, 17, 23, 29, 31, 41, 43, 47, 53, 59, 71, 83, 89, 101, 107, 109, 113, 127, 131, 137, 149, 157, 167, 173, 179, 191, 197, 223, 227, 229, 233, 239, 251, 257, 263, 269, 277, 281, 283, 293, 307, 311, 317, 347, 353, 359, 383, 389, 397, 401, 419, 431, 433
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OFFSET
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1,1
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COMMENTS
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This is the union of {3}, A003627 (primes congruent to 2 mod 3) and A014752 (primes of the form x^2+27y^2). By Thm. 4.15 of [Cox], p is of the form x^2+27y^2 if and only if p is congruent to 1 mod 3 and 2 is a cubic residue mod p. If p is not congruent to 1 mod 3, then every number is a cubic residue mod p, including 2. - Andrew V. Sutherland, Apr 26 2008
Complement of A040034 relative to A000040. - Vincenzo Librandi, Sep 13 2012
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REFERENCES
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David A. Cox, "Primes of the Form x^2+ny^2", 1998, John Wiley & Sons.
Kenneth Ireland and Michael Rosen, "A Classical Introduction to Modern Number Theory", second ed., 1990, Springer-Verlag.
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LINKS
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T. D. Noe, Table of n, a(n) for n = 1..1000
Index entries for related sequences
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FORMULA
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a(n) ~ (3/2) n log n. - Charles R Greathouse IV, Apr 06 2022
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MATHEMATICA
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f[p_] := Block[{k = 2}, While[k < p && Mod[k^3, p] != 2, k++ ]; If[k == p, 0, 1]]; Select[ Prime[ Range[100]], f[ # ] == 1 &] (* Robert G. Wilson v, Jul 26 2004 *)
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PROG
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(Magma) [ p: p in PrimesUpTo(433) | exists(t){x : x in ResidueClassRing(p) | x^3 eq 2} ]; // Klaus Brockhaus, Dec 02 2008
(PARI) select(p->ispower(Mod(2, p), 3), primes(100)) \\ Charles R Greathouse IV, Apr 28 2015
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CROSSREFS
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Cf. A001132. Number of primes p < 10^n for which 2 is a cubic residue (mod p) is in A097142.
Cf. A000040, A003627, A014572, A040034.
For primes p such that x^m == 2 mod p has a solution for m = 2,3,4,5,6,7,... see A038873, A040028, A040098, A040159, A040992, A042966, ...
Sequence in context: A079545 A154755 A040095 * A049589 A049583 A049596
Adjacent sequences: A040025 A040026 A040027 * A040029 A040030 A040031
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KEYWORD
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nonn,easy
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AUTHOR
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N. J. A. Sloane
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EXTENSIONS
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Typo corrected to A014752 by Paul Landon (paullandon(AT)hotmail.com), Jan 25 2010
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STATUS
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approved
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