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A007693 Numbers n such that n and 6n+1 are primes.
(Formerly M0656)
17
2, 3, 5, 7, 11, 13, 17, 23, 37, 47, 61, 73, 83, 101, 103, 107, 131, 137, 151, 173, 181, 233, 241, 257, 263, 271, 277, 283, 293, 311, 313, 331, 347, 367, 373, 397, 443, 461, 467, 503, 557, 577, 593, 601, 607, 641, 653, 661, 683, 727, 751, 761, 773, 787, 797, 853 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Solutions of the equation (6*n+1)' + n' = 2, where n' is the arithmetic derivative of n. [Paolo P. Lava, Oct 31 2012]

REFERENCES

Andrew Granville, Sophie Germain's theorem for prime pairs p, 6p+1, J. Number Theory 27 (1987), no. 1, 63-72.

J. Roberts, Lure of the Integers, Math. Assoc. America, 1992, p. 27983

N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

LINKS

Harvey P. Dale, Table of n, a(n) for n = 1..1000

FORMULA

a(n) = (A051644(n)-1)/6.

MATHEMATICA

Select[Prime@Range[150], PrimeQ[6# + 1] &] (*Chandler*)

PROG

(MAGMA) [n: n in [0..1000] | IsPrime(n) and IsPrime(6*n+1)] [V. Librandi, Nov 18 2010]

CROSSREFS

Cf. A002476, A016921, A024899, A051644, A091178.

Prime terms of A024899.

Sequence in context: A175584 A216823 A152245 * A174048 A103144 A105909

Adjacent sequences:  A007690 A007691 A007692 * A007694 A007695 A007696

KEYWORD

nonn,easy

AUTHOR

N. J. A. Sloane, Robert G. Wilson v

EXTENSIONS

Extended by Ray Chandler, Mar 14 2007

STATUS

approved

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Last modified June 20 08:41 EDT 2013. Contains 226422 sequences.