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A051647 Primes p such that 210*p + 1 is also prime. 2
2, 3, 5, 7, 11, 13, 17, 23, 29, 47, 53, 59, 67, 73, 83, 89, 101, 137, 139, 157, 163, 179, 181, 191, 193, 223, 229, 251, 271, 277, 281, 313, 317, 347, 349, 353, 359, 401, 419, 421, 431, 433, 449, 457, 463, 479, 523, 577, 599, 601, 631, 653, 701, 709, 719, 727 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Analogous to A005384, Sophie Germain primes.

LINKS

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

EXAMPLE

A002110(4)*p + 1 = 210*p + 1 and p are both primes.

11 is in the sequence because 210*11 + 1 = 2311 is also prime.

MATHEMATICA

Select[Prime[Range[200]], PrimeQ[210#+1]&]  (* Harvey P. Dale, Apr 25 2011 *)

PROG

(MAGMA) [p: p in PrimesUpTo(900) | IsPrime(210*p+1)]; // Vincenzo Librandi, Apr 11 2013

CROSSREFS

Cf. A005384, A005385, A007693.

Sequence in context: A181659 A040087 A040065 * A042986 A143390 A038617

Adjacent sequences:  A051644 A051645 A051646 * A051648 A051649 A051650

KEYWORD

nonn,easy

AUTHOR

Labos Elemer

STATUS

approved

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Last modified May 19 10:36 EDT 2019. Contains 323390 sequences. (Running on oeis4.)