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Search: id:A007693
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| A007693 |
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Numbers n such that n and 6n+1 are primes.
(Formerly M0656)
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+0
14
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| 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; listen)
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OFFSET
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1,1
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REFERENCES
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N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
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
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FORMULA
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a(n) = (A051644(n)-1)/6.
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MATHEMATICA
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Select[Prime@Range[150], PrimeQ[6# + 1] &] (*Chandler*)
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CROSSREFS
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Cf. A002476, A016921, A024899, A051644, A091178.
Adjacent sequences: A007690 A007691 A007692 this_sequence A007694 A007695 A007696
Sequence in context: A068669 A100553 A152245 this_sequence A103144 A105909 A086498
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KEYWORD
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nonn,easy
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AUTHOR
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N. J. A. Sloane (njas(AT)research.att.com), Robert G. Wilson v (rgwv(AT)rgwv.com)
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EXTENSIONS
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Extended by Ray Chandler (rayjchandler(AT)sbcglobal.net), Mar 14 2007
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