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 A030469 Primes which are concatenations of three consecutive primes. 17
 5711, 111317, 171923, 313741, 414347, 8997101, 229233239, 239241251, 263269271, 307311313, 313317331, 317331337, 353359367, 359367373, 383389397, 389397401, 401409419, 409419421, 439443449, 449457461 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS a(n) = "p(k) p(k+1) p(k+2)" where p(k) is k-th prime It is conjectured that sequence is infinite. - from Eva-Maria Zschorn (e-m.zschorn(AT)zaschendorf.km3.de), Nov 09 2009 REFERENCES Richard E. Crandall, Carl Pomerance: Prime Numbers, Springer 2005 - from Eva-Maria Zschorn (e-m.zschorn(AT)zaschendorf.km3.de), Nov 09 2009 John Derbyshire: Prime obsession, Joseph Henry Press, Washington, DC 2003 - from Eva-Maria Zschorn (e-m.zschorn(AT)zaschendorf.km3.de), Nov 09 2009 Marcus du Sautoy: Die Musik der Primzahlen. Auf den Spuren des groessten Raetsels der Mathematik, Beck, Muenchen 2004 LINKS Zak Seidov, Table of n, a(n) for n = 1..1000 FORMULA A132903 INTERSECT A000040. - R. J. Mathar, Nov 11 2009 EXAMPLE (1) 5=p(3), 7=p(4), 11=p(5) gives a(1). (2) 7=p(4), 11=p(5), 13=p(6), but 71113 = 7 x 10159 MATHEMATICA Select[Table[FromDigits[Flatten[IntegerDigits/@{Prime[n], Prime[n+1], Prime[n+2]}]], {n, 11000}], PrimeQ] (* Zak Seidov, Oct 16 2009 *) concat[{a_, b_, c_}]:=FromDigits[Flatten[IntegerDigits/@{a, b, c}]]; Select[ concat/@ Partition[ Prime[ Range[200]], 3, 1], PrimeQ] (* Harvey P. Dale, Sep 06 2017 *) PROG (PARI) for(i=1, 999, isprime(p=eval(Str(prime(i), prime(i+1), prime(i+2)))) & print1(p, " ")) \\ M. F. Hasler, Nov 10 2009 CROSSREFS Cf. A030461, A167517, A132903, A068655, A030997, A030473, A086041, A099727. Sequence in context: A252342 A237743 A025027 * A244163 A253423 A202376 Adjacent sequences:  A030466 A030467 A030468 * A030470 A030471 A030472 KEYWORD nonn,base AUTHOR STATUS approved

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Last modified May 9 05:11 EDT 2021. Contains 343688 sequences. (Running on oeis4.)