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A055667 Number of Eisenstein-Jacobi primes of norm n. +0
5
0, 0, 0, 6, 6, 0, 0, 12, 0, 0, 0, 0, 0, 12, 0, 0, 0, 0, 0, 12, 0, 0, 0, 0, 0, 6, 0, 0, 0, 0, 0, 12, 0, 0, 0, 0, 0, 12, 0, 0, 0, 0, 0, 12, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 12, 0, 0, 0, 0, 0, 12, 0, 0, 0, 0, 0, 12, 0, 0, 0, 0, 0, 12, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 12, 0, 0 (list; graph; listen)
OFFSET

0,4

COMMENT

These are the primes in the ring of integers a+b*omega, a and b rational integers, omega = (1+sqrt(-3))/2.

REFERENCES

R. K. Guy, Unsolved Problems in Number Theory, A16.

L. W. Reid, The Elements of the Theory of Algebraic Numbers, MacMillan, NY, 1910, see Chap. VI.

FORMULA

a(n) = 6 * A055668(n) - Frank Adams-Watters (FrankTAW(AT)Netscape.net), May 05 2006

EXAMPLE

There are 6 Eisenstein-Jacobi primes of norm 3, omega-omega^2 times one of the 6 units [ +-1, +-omega, +-omega^2 ] but only one up to equivalence.

CROSSREFS

Cf. A055664-A055668, A055025-A055029, A135461, A135462. See A004016 and A035019 for theta series of Eisenstein (or hexagonal) lattice.

Sequence in context: A028971 A006806 A002892 this_sequence A005597 A081825 A028969

Adjacent sequences: A055664 A055665 A055666 this_sequence A055668 A055669 A055670

KEYWORD

nonn,easy,nice

AUTHOR

njas, Jun 09 2000

EXTENSIONS

More terms from Frank Adams-Watters (FrankTAW(AT)Netscape.net), May 05 2006

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Last modified July 4 18:25 EDT 2008. Contains 140886 sequences.


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