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A088878
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Prime numbers p such that 3p-2 is a prime.
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37
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3, 5, 7, 11, 13, 23, 37, 43, 47, 53, 61, 67, 71, 103, 113, 127, 137, 163, 167, 181, 191, 193, 211, 251, 257, 263, 271, 277, 293, 307, 313, 331, 337, 347, 373, 401, 431, 433, 443, 461, 467, 487, 491, 523, 541, 557, 587, 593, 601, 673, 677, 727, 751, 757, 761
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OFFSET
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1,1
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COMMENTS
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Indices of semiprime octagonal numbers. - Jonathan Vos Post, Feb 16 2006
Daughter primes of order 1. - Artur Jasinski, Dec 12 2007
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REFERENCES
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M. Cerasoli, F. Eugeni and M. Protasi, Elementi di Matematica Discreta, Bologna 1988
Emanuele Munarini and Norma Zagaglia Salvi, Matematica Discreta,UTET, CittaStudiEdizioni, Milano 1997
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LINKS
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Vincenzo Librandi, Table of n, a(n) for n = 1..1000
Eric Weisstein's World of Mathematics, Octagonal Number.
Eric Weisstein's World of Mathematics, Semiprime.
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EXAMPLE
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For p=3, 3p-2=7; for p=523, 3p-2=1567
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MATHEMATICA
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lst={}; Do[p=Prime[n]; If[PrimeQ[3*p-2], AppendTo[lst, p]], {n, 5!}]; lst (*From Vladimir Joseph Stephan Orlovsky, Dec 22 2008 *)
n = 1; a = {}; Do[If[PrimeQ[(Prime[k] + 2n)/(2n + 1)], AppendTo[a, (Prime[k] + 2n)/(2n + 1)]], {k, 1, 500}]; a (* Artur Jasinski, Dec 12 2007 *)
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PROG
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(MAGMA) [ p: p in PrimesUpTo(770) | IsPrime(3*p-2) ]; - Klaus Brockhaus, Dec 21 2008
(PARI) list(lim)=select(p->isprime(3*p-2), primes(primepi(lim))) \\ Charles R Greathouse IV, Jul 25 2011
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CROSSREFS
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Cf. A000040, A000567, A001222, A001358, A091179, A091180, A091181, A136019, A136020, A153183, A153184.
Sequence in context: A181741 A154319 A080114 * A155916 A038979 A179739
Adjacent sequences: A088875 A088876 A088877 * A088879 A088880 A088881
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KEYWORD
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easy,nonn
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AUTHOR
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Giovanni Teofilatto, Nov 27 2003
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EXTENSIONS
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Corrected and extended by Ray Chandler, Dec 27 2003
Entry revised by N. J. A. Sloane, Nov 28 2006, Jul 08 2010
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STATUS
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approved
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