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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
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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; refs; listen; history; internal format)
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OFFSET
| 1,1
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EXAMPLE
| 7 is prime, 2*7+1 = 15 is composite, so a(1) = 7*2 = 14.
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MAPLE
| 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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PROG
| (PARI) forprime (p=3, 200, if (isprime(2*p+1), print1(2*p", ")))
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CROSSREFS
| Cf. A005277.
Equals 2 * A053176.
Sequence in context: A134837 A105583 A005277 * A176274 A191992 A082773
Adjacent sequences: A079699 A079700 A079701 * A079703 A079704 A079705
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KEYWORD
| nonn,easy
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AUTHOR
| Jon Perry (perry(AT)globalnet.co.uk), Jan 31 2003
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EXTENSIONS
| More terms from Emeric Deutsch (deutsch(AT)duke.poly.edu), Jul 25 2006
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