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A051647 Primes p such that 210p+1 is also prime. 1
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; internal format)
OFFSET

1,1

COMMENTS

Analogous to A005384, Sophie Germain primes.

FORMULA

p and A002110[4]*p+1=210p+1 are both primes

EXAMPLE

Both 11 and 210*11+1=2311 are primes

MATHEMATICA

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

CROSSREFS

A005384, A005385, A007693.

Sequence in context: A181659 A040087 A040065 * A042986 A143390 A038617

Adjacent sequences:  A051644 A051645 A051646 * A051648 A051649 A051650

KEYWORD

nonn

AUTHOR

Labos E. (labos(AT)ana.sote.hu)

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Last modified February 15 09:35 EST 2012. Contains 205753 sequences.