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A033207
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Primes of form x^2+7*y^2.
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9
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7, 11, 23, 29, 37, 43, 53, 67, 71, 79, 107, 109, 113, 127, 137, 149, 151, 163, 179, 191, 193, 197, 211, 233, 239, 263, 277, 281, 317, 331, 337, 347, 359, 373, 379, 389, 401, 421, 431, 443, 449, 457, 463, 487, 491
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OFFSET
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1,1
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COMMENTS
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Primes (other than 7) which can be written in the form a^2 + 7*b^2, a > 0 and b > 0. - V. Raman, Sep 08 2012
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REFERENCES
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D. Cox, "Primes of Form x^2 + n y^2", Wiley, 1989.
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LINKS
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T. D. Noe, Table of n, a(n) for n = 1..1000
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FORMULA
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Primes congruent to {1, 7, 9, 11, 15, 23, 25} (mod 28). - T. D. Noe, Apr 29 2008
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MATHEMATICA
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QuadPrimes[1, 0, 7, 10000] (* see A106856 *)
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PROG
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(PARI) is(n)=kronecker(n, 7)>=0 && isprime(n) && n>2 \\ Charles R Greathouse IV, Nov 19 2012
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CROSSREFS
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Essentially the same as A045373. Primes in A020670.
Cf. A002344, A002345, A139643.
Sequence in context: A211433 A039511 A103667 * A095084 A182569 A067790
Adjacent sequences: A033204 A033205 A033206 * A033208 A033209 A033210
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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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STATUS
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approved
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