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Search: id:A162712
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| A162712 |
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Primes p such that 3^p-2^p-2 is also prime. |
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2
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OFFSET
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1,1
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COMMENT
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The associated 3^p-2^p-2 are in A162713.
The list of k such that 3^k-2^k-2 is prime is k=2, 3, 43, 61, 63, 1369,... where 63 and 1369 are not prime.
Contribution from Emeric Deutsch (deutsch(AT)duke.poly.edu), Aug 03 2009: (Start)
No other term <=15000.
(End)
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EXAMPLE
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p=2 is in the sequence because 3^2-2^2-2=3 is prime. p=3 is in the sequence because 3^3-2^3-2=17 is prime.
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MAPLE
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a := proc (n) if isprime(n) = true and isprime(3^n-2^n-2) = true then n else end if end proc: seq(a(n), n = 1 .. 15000); [From Emeric Deutsch (deutsch(AT)duke.poly.edu), Aug 03 2009]
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CROSSREFS
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Cf. A162713.
Sequence in context: A087571 A126018 A051099 this_sequence A062581 A077520 A100015
Adjacent sequences: A162709 A162710 A162711 this_sequence A162713 A162714 A162715
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KEYWORD
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nonn
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AUTHOR
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Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Jul 11 2009
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EXTENSIONS
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Edited by R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Jul 26 2009
a(5) and a(6) from Emeric Deutsch (deutsch(AT)duke.poly.edu), Aug 03 2009
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