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

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A050265 Primes of the form 2*n^2 + 11. 47
11, 13, 19, 29, 43, 61, 83, 109, 139, 173, 211, 349, 461, 523, 659, 733, 811, 1069, 1163, 1579, 1693, 1811, 1933, 2749, 3373, 3539, 3709, 4243, 4813, 5011, 5419, 5843, 7211, 7699, 7949, 8461, 9533, 9811, 10093, 11261, 13789, 14461, 15149, 16573 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

The polynomial 2*n^2 + 11 first fails to produce a prime for n = 11, giving 253 = 11 * 23. - Alonso del Arte, Sep 04 2016

Let P(n) = 2*n^2 + 11. The polynomial P(2*n - 10) = 8*n^2 - 80*n + 11 produces prime values (not distinct) for n = 0 to 10. The polynomial P(3*n - 19) = 18*n^2 - 228*n + 733 produces distinct prime values for n = 0 to 9. - Peter Bala, Apr 16 2018

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 1..10000

Eric Weisstein's World of Mathematics, Prime-generating Polynomial.

FORMULA

a(n) = 11 + 2*(A092968(n))^2. - R. J. Mathar, Jan 03 2009

MATHEMATICA

Select[2Range[0, 100]^2 + 11, PrimeQ] (* Harvey P. Dale, May 20 2011 *)

PROG

(MAGMA) [a: n in [0..100] | IsPrime(a) where a is 2*n^2+11]; // Vincenzo Librandi, Dec 08 2011

CROSSREFS

Cf. A005846, A007641.

Sequence in context: A284037 A321891 A153421 * A176871 A092402 A081983

Adjacent sequences:  A050262 A050263 A050264 * A050266 A050267 A050268

KEYWORD

nonn,easy

AUTHOR

Eric W. Weisstein

EXTENSIONS

11 added by Vincenzo Librandi, Dec 08 2011

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 May 24 04:25 EDT 2019. Contains 323528 sequences. (Running on oeis4.)