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A005234
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Primorial primes: primes p such that 1 + product of primes up to p is prime.
(Formerly M0669)
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18
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2, 3, 5, 7, 11, 31, 379, 1019, 1021, 2657, 3229, 4547, 4787, 11549, 13649, 18523, 23801, 24029, 42209, 145823, 366439, 392113
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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REFERENCES
| C. K. Caldwell and Y. Gallot, On the primality of n!+-1 and 2*3*5*...*p+-1, Math. Comp., 71 (2001), 441-448.
J.-M. De Koninck, Ces nombres qui nous fascinent, Entry 211, p. 61, Ellipses, Paris 2008.
H. Dubner, A new primorial prime, J. Rec. Math., 21 (No. 4, 1989), 276.
R. K. Guy, Unsolved Problems in Number Theory, Section A2.
Paulo Ribenboim, The New Book of Prime Number Records, p. 13.
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
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LINKS
| C. K. Caldwell, Primorial Primes
R. Ondrejka, The Top Ten: a Catalogue of Primal Configurations
Eric Weisstein's World of Mathematics, Link to a section of The World of Mathematics.
Eric Weisstein's World of Mathematics, Link to a section of The World of Mathematics.
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CROSSREFS
| A014545 gives same sequence in another form, namely values of n such that 1 + product of first n primes is prime. Cf. A002110, A006862, A006794, A057704. A018239 gives the actual primes.
Sequence in context: A119388 A093487 A067933 * A140561 A140553 A195337
Adjacent sequences: A005231 A005232 A005233 * A005235 A005236 A005237
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KEYWORD
| nonn,hard,nice
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AUTHOR
| N. J. A. Sloane (njas(AT)research.att.com).
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EXTENSIONS
| 42209 sent in by Chris Nash (chrisnash(AT)cwix.com).
145823 discovered and sent in by Arlin Anderson (starship1(AT)gmail.com) and Don Robinson (donald.robinson(AT)itt.com), Jun 01 2000
366439, 392113 from Eric Weisstein (eric(AT)weisstein.com), Mar 13 2004 (based on information in A057704)
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