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Search: id:A154524
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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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3
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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; listen)
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OFFSET
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1,1
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FORMULA
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A057825 INTERSECT A000040. [From R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Jan 14 2009]
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EXAMPLE
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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
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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
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Cf. A056604, A154525, A154526.
Sequence in context: A052333 A074106 A002261 this_sequence A079131 A106919 A005850
Adjacent sequences: A154521 A154522 A154523 this_sequence A154525 A154526 A154527
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KEYWORD
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nonn
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AUTHOR
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Lekraj Beedassy (blekraj(AT)yahoo.com), Jan 11 2009
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EXTENSIONS
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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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