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A154524
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Primes p such that LCM[1,2,3,...,p-2,p-1,p] - 1 is prime.
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2
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3, 5, 7, 19, 23, 29, 47, 61, 97, 181, 233, 307, 401, 887, 1021, 1087, 1361, 1481, 2053, 2293, 5407, 5857
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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FORMULA
| A057825 INTERSECT A000040. [From R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Jan 14 2009]
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EXAMPLE
| 7 is in the sequence because it is prime and also LCM(1,2,3,4,5,6,7)-1=420-1=419 is prime. [From Emeric Deutsch (deutsch(AT)duke.poly.edu), Jan 16 2009]
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MAPLE
| P := proc (n) options operator, arrow: lcm(seq(j, j = 1 .. n)) end proc: a := proc (n) if isprime(n) = true and isprime(P(n)-1) = true then n else end if end proc: seq(a(n), n = 1 .. 3000); [From Emeric Deutsch (deutsch(AT)duke.poly.edu), Jan 16 2009]
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CROSSREFS
| Cf. A056604, A154525, A154526.
Sequence in context: A052333 A074106 A002261 * A184805 A079131 A179687
Adjacent sequences: A154521 A154522 A154523 * A154525 A154526 A154527
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KEYWORD
| nonn
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AUTHOR
| Lekraj Beedassy (blekraj(AT)yahoo.com), Jan 11 2009
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EXTENSIONS
| a(8)-a(27) from Ray Chandler (rayjchandler(AT)sbcglobal.net), Jan 16 2009
More terms from Emeric Deutsch (deutsch(AT)duke.poly.edu), Jan 16 2009
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