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A084865 Primes of the form 2x^2 + 3y^2. +0
6
2, 3, 5, 11, 29, 53, 59, 83, 101, 107, 131, 149, 173, 179, 197, 227, 251, 269, 293, 317, 347, 389, 419, 443, 461, 467, 491, 509, 557, 563, 587, 653, 659, 677, 683, 701, 773, 797, 821, 827, 941, 947, 971, 1013, 1019, 1061, 1091, 1109, 1163, 1181, 1187 (list; graph; listen)
OFFSET

1,1

COMMENT

Subsequence of A084864; A084863(a(n))>0.

Conjecture: A084863(a(n))=1?

Is it true that a(n) = A019338(n+1)?

Comment: The truth of the conjecture A084863(a(n))=1 follows from the genus theory of quadratic forms (see Cox, page 61). By comparing enough terms, we see that the conjecture a(n) = A019338(n+1) is false. - T. D. Noe (noe(AT)sspectra.com), May 02 2008

REFERENCES

David A. Cox, Primes of Form x^2 + n y^2, Wiley, 1989.

FORMULA

The primes are congruent to {2, 3, 5, 11} (mod 24). - T. D. Noe (noe(AT)sspectra.com), May 02 2008

EXAMPLE

A000040(17) = 59 = 32 + 27 = 2*4^2 + 3*3^2, therefore 59 is a term.

CROSSREFS

Cf. A084866.

Cf. A139827.

Sequence in context: A055228 A098642 A079447 this_sequence A047934 A090235 A103596

Adjacent sequences: A084862 A084863 A084864 this_sequence A084866 A084867 A084868

KEYWORD

nonn

AUTHOR

Reinhard Zumkeller (reinhard.zumkeller(AT)lhsystems.com), Jun 10 2003

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Last modified August 19 23:53 EDT 2008. Contains 142930 sequences.


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