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A034017 Numbers that are primitively represented by x^2+xy+y^2. 3
0, 1, 3, 7, 13, 19, 21, 31, 37, 39, 43, 49, 57, 61, 67, 73, 79, 91, 93, 97, 103, 109, 111, 127, 129, 133, 139, 147, 151, 157, 163, 169, 181, 183, 193, 199, 201, 211, 217, 219, 223, 229, 237, 241, 247, 259, 271, 273, 277, 283, 291, 301, 307, 309, 313, 327, 331 (list; graph; refs; listen; history; internal format)
OFFSET

1,3

COMMENTS

Gives the location of the nonzero terms of A000086.

REFERENCES

B. C. Berndt & R. A. Rankin, Ramanujan: Letters and Commentary, see p. 184, AMS Providence RI 1995.

LINKS

Linda Stannard, Principles of Virus Architecture

FORMULA

3^{0 or 1} X product of primes of form 3a+1 to any power.

CROSSREFS

Cf. A003136, A045611, A045897.

Sequence in context: A032437 A076746 A118667 * A034021 A038978 A133387

Adjacent sequences:  A034014 A034015 A034016 * A034018 A034019 A034020

KEYWORD

nonn

AUTHOR

N. J. A. Sloane (njas(AT)research.att.com).

EXTENSIONS

Extended by Ray Chandler (rayjchandler(AT)sbcglobal.net), Jan 29 2009

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Last modified February 16 12:15 EST 2012. Contains 205909 sequences.