login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A029718 Numbers of form 2x^2 + 2xy + 3y^2. 2
0, 2, 3, 7, 8, 10, 12, 15, 18, 23, 27, 28, 32, 35, 40, 42, 43, 47, 48, 50, 58, 60, 63, 67, 72, 75, 82, 83, 87, 90, 92, 98, 103, 107, 108, 112, 115, 122, 123, 127, 128, 135, 138, 140, 147, 160, 162, 163, 167, 168, 172, 175, 178, 183, 188, 192, 200, 202, 203, 207, 210 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Numbers represented by quadratic form with Gram matrix [ 2, 1; 1, 3 ].

REFERENCES

H. Cohn, A second course in number theory, John Wiley & Sons, Inc., New York-London, 1962. see page 3.

LINKS

Table of n, a(n) for n=1..61.

N. J. A. Sloane et al., Binary Quadratic Forms and OEIS (Index to related sequences, programs, references)

FORMULA

List contains 0 and all positive n such that 2*A035170(n) = A028586(n) is nonzero. - Michael Somos, Oct 21 2006

CROSSREFS

Cf. A028927.

For primes see A106865.

Sequence in context: A047532 A225378 A028808 * A206821 A323003 A051468

Adjacent sequences:  A029715 A029716 A029717 * A029719 A029720 A029721

KEYWORD

nonn

AUTHOR

N. J. A. Sloane

EXTENSIONS

More terms from Larry Reeves (larryr(AT)acm.org), Mar 29 2000

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified July 19 11:10 EDT 2019. Contains 325155 sequences. (Running on oeis4.)