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A062721
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Numbers n such that n is a product of two primes and n-2 is prime.
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8
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4, 9, 15, 21, 25, 33, 39, 49, 55, 69, 85, 91, 111, 115, 129, 133, 141, 159, 169, 183, 201, 213, 235, 253, 259, 265, 295, 309, 319, 339, 355, 361, 381, 391, 403, 411, 445, 451, 469, 481, 489, 493, 501, 505, 511, 543, 559, 565, 573, 579, 589, 633, 649, 655, 679
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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LINKS
| Zak Seidov, Table of n, a(n) for n=1..10000.
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MATHEMATICA
| Select[ Range[ 2, 1500 ], Plus @@ Last@Transpose@FactorInteger[ # ] == 2 && PrimeQ[ # - 2 ] & ]
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PROG
| (PARI) { n=0; for (m=1, 10^9, a=prime(m) + 2; f=factor(a)~; if ((length(f)==1 && f[2, 1]==2) || (length(f)==2 && f[2, 1]==1 && f[2, 2]==1), write("b062721.txt", n++, " ", a); if (n==10000, break)) ) } [From Harry J. Smith (hjsmithh(AT)sbcglobal.net), Aug 09 2009]
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CROSSREFS
| Cf. A006512, A001358, A043326.
Cf. A063637, A046315, A089268.
Sequence in context: A122927 A078505 A107986 * A104243 A099055 A162801
Adjacent sequences: A062718 A062719 A062720 * A062722 A062723 A062724
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KEYWORD
| nonn
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AUTHOR
| Ahmed Fares (ahmedfares(AT)my-deja.com), Jul 14 2001
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