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Search: id:A079702
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| A079702 |
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Numbers 2p where p is prime and 2p+1 is composite. |
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+0
1
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| 14, 26, 34, 38, 62, 74, 86, 94, 118, 122, 134, 142, 146, 158, 194, 202, 206, 214, 218, 254, 274, 278, 298, 302, 314, 326, 334, 362, 386, 394, 398, 422, 446, 454, 458, 482, 514, 526, 538, 542, 554, 566, 614, 622, 626, 634, 662, 674, 694, 698, 706, 734, 746
(list; graph; listen)
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OFFSET
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1,1
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EXAMPLE
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7 is prime, 2*7+1 = 15 is composite, so a(1) = 7*2 = 14.
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MAPLE
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a:=proc(n) if isprime(2*ithprime(n)+1)=false then 2*ithprime(n) else fi end: seq(a(n), n=1..100); - Emeric Deutsch (deutsch(AT)duke.poly.edu), Jul 25 2006
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PROGRAM
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(PARI) forprime (p=3, 200, if (isprime(2*p+1), print1(2*p", ")))
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CROSSREFS
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Cf. A005277.
Equals 2 * A053176.
Sequence in context: A094163 A105583 A005277 this_sequence A082773 A112772 A086258
Adjacent sequences: A079699 A079700 A079701 this_sequence A079703 A079704 A079705
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KEYWORD
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nonn,easy
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AUTHOR
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Jon Perry (perry(AT)globalnet.co.uk), Jan 31 2003
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EXTENSIONS
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More terms from Emeric Deutsch (deutsch(AT)duke.poly.edu), Jul 25 2006
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