login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A139992 Primes of the form 20x^2+20xy+47y^2. 2
47, 167, 383, 503, 647, 887, 983, 1223, 1487, 1823, 1847, 2063, 2663, 2687, 2903, 3023, 3167, 3407, 3527, 3863, 4007, 4583, 4703, 5087, 5927, 6047, 6263, 6863, 7103, 7607, 7703, 7727, 8447, 8543, 8783, 9623, 9743, 9887, 10223, 10247, 10463 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Discriminant=-3360. See A139827 for more information.

Also primes of the forms 47x^2+40xy+80y^2 and 47x^2+42xy+63y^2. See A140633. - T. D. Noe, May 19 2008

LINKS

Vincenzo Librandi and Ray Chandler, Table of n, a(n) for n = 1..10000 [First 1000 terms from Vincenzo Librandi]

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

FORMULA

The primes are congruent to {47, 143, 167, 383, 503, 647} (mod 840).

MATHEMATICA

QuadPrimes2[20, -20, 47, 10000] (* see A106856 *)

PROG

(MAGMA) [p: p in PrimesUpTo(12000) | p mod 840 in [47, 143, 167, 383, 503, 647]]; // Vincenzo Librandi, Aug 03 2012

CROSSREFS

Sequence in context: A132251 A078857 A216827 * A142916 A253351 A253344

Adjacent sequences:  A139989 A139990 A139991 * A139993 A139994 A139995

KEYWORD

nonn,easy

AUTHOR

T. D. Noe, May 02 2008

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 January 23 14:29 EST 2022. Contains 350512 sequences. (Running on oeis4.)