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A051644 Primes of the form 6p+1 where p is also prime. 11
13, 19, 31, 43, 67, 79, 103, 139, 223, 283, 367, 439, 499, 607, 619, 643, 787, 823, 907, 1039, 1087, 1399, 1447, 1543, 1579, 1627, 1663, 1699, 1759, 1867, 1879, 1987, 2083, 2203, 2239, 2383, 2659, 2767, 2803, 3019, 3343, 3463, 3559, 3607, 3643, 3847, 3919 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Analogous to A005385; can be called 6-safe primes.

LINKS

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

FORMULA

a(n) = 6*A007693(n) + 1.

EXAMPLE

103 is here because it is prime and (103-1)/6=17 is prime.

MATHEMATICA

Select[1 + 6Prime@Range[120], PrimeQ] (* Ray Chandler, Mar 14 2007 *)

CROSSREFS

Cf. A005384, A005385, A002476, A007693, A016921, A024899, A091178.

Sequence in context: A069324 A040047 A163847 * A101408 A023252 A279426

Adjacent sequences:  A051641 A051642 A051643 * A051645 A051646 A051647

KEYWORD

nonn

AUTHOR

Labos Elemer

EXTENSIONS

Edited, corrected and extended by Ray Chandler, Mar 14 2007

STATUS

approved

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Last modified June 24 08:22 EDT 2017. Contains 288697 sequences.