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

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A172122 Primes p such that 7*p^2+7*p+1 is also prime. 1
2, 5, 17, 29, 59, 197, 227, 257, 317, 359, 467, 509, 569, 587, 797, 929, 1097, 1187, 1259, 1307, 1439, 1637, 1697, 1847, 1877, 1997, 2027, 2069, 2099, 2237, 2297, 2399, 2459, 2477, 2657, 2687, 2729, 2939, 3167, 3359, 3407, 3467, 3659, 3677, 4019, 4079 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 1..1000

MATHEMATICA

Select[Prime[Range[3000]], PrimeQ[7 #^2 + 7 # + 1]&] (* Vincenzo Librandi, Apr 16 2013 *)

PROG

(MAGMA) [p: p in PrimesUpTo(4100) | IsPrime(7*p^2 + 7*p + 1)]; // Vincenzo Librandi, Apr 16 2013

CROSSREFS

Cf. A171139.

Sequence in context: A244085 A019353 A106882 * A101009 A269018 A066649

Adjacent sequences:  A172119 A172120 A172121 * A172123 A172124 A172125

KEYWORD

nonn,easy

AUTHOR

Vincenzo Librandi, Jan 26 2010

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 November 13 00:25 EST 2019. Contains 329083 sequences. (Running on oeis4.)