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Search: id:A153645
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| A153645 |
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Primes p such p^2+4 and p^2+4p+2 are also prime. |
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+0
1
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| 3, 5, 7, 13, 17, 47, 67, 73, 137, 167, 277, 307, 313, 487, 503, 593, 607, 613, 787, 823, 1117, 1123, 1237, 1523, 1543, 1637, 1987, 2777, 2887, 3037, 3163, 3433, 3457, 3463, 3797, 3853, 4093, 4283, 4583, 5113, 5297, 5323, 5683, 5953, 6047, 6577, 6803, 6823
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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Subsequence of A062324.
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EXAMPLE
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For prime p = 3, p^2+4 = 13 and p^2+4p+2 = 23 are prime; for p = 67, p^2+4 = 4493 and p^2+4p+2 = 4759 are prime.
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MAPLE
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a := proc (n) if isprime(n) = true and isprime(n^2+4) = true and isprime(n^2+4*n+2) = true then n else end if end proc: seq(a(n), n = 1 .. 7000); [From Emeric Deutsch (deutsch(AT)duke.poly.edu), Jan 02 2009]
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PROGRAM
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(MAGMA) [ p: p in PrimesUpTo(7000) | IsPrime(p^2+4) and IsPrime(p^2+4*p+2) ];
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CROSSREFS
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Cf. A062324 (p and p^2+4 are both prime).
Sequence in context: A073638 A066464 A062324 this_sequence A106878 A079481 A075571
Adjacent sequences: A153642 A153643 A153644 this_sequence A153646 A153647 A153648
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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), Dec 30 2008
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EXTENSIONS
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Edited, corrected (three terms deleted) and extended beyond a(10) by Klaus Brockhaus (klaus-brockhaus(AT)t-online.de), Jan 02 2009
Corrected and extended by Emeric Deutsch (deutsch(AT)duke.poly.edu), Jan 02 2009
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