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Search: id:A166009
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| A166009 |
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Primes of the form 7+2*(some other prime). |
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+0
1
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| 11, 13, 17, 29, 41, 53, 89, 101, 113, 149, 173, 233, 269, 281, 353, 389, 401, 461, 509, 521, 569, 593, 641, 701, 773, 809, 929, 941, 1013, 1049, 1181, 1193, 1289, 1301, 1361, 1373, 1409, 1493, 1553, 1601, 1721, 1733, 1889, 1901, 1913, 1949, 1973, 2069, 2129
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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Starting with n=3 both A166009(n) and A023206(n) == 5 mod 6. [From Zak Seidov (zakseidov(AT)yahoo.com), Oct 23 2009]
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FORMULA
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a(n) = 7+2*A023206(n). - R. J. Mathar, Oct 05 2009
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EXAMPLE
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p=2 contributes 11=7+2*2. p=3 contributes 13=7+2*3. p=5 contributes 17=7+2*5.
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MATHEMATICA
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Clear[lst, n, f] f[n_]:=PrimeQ[(n-1)/2-3]; lst={}; Do[p=Prime[n]; If[f[p], AppendTo[lst, p]], {n, 7!}]; lst [From Vladimir Orlovsky (4vladimir(AT)gmail.com), Oct 13 2009]
s={11, 13}; Do[If[PrimeQ[n]&&PrimeQ[(n-7)/2], AppendTo[s, n]], {n, 17, 10^3, 6}]; s [From Zak Seidov (zakseidov(AT)yahoo.com), Oct 23 2009]
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CROSSREFS
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Cf. A023206. [From Zak Seidov (zakseidov(AT)yahoo.com), Oct 23 2009]
Sequence in context: A006489 A032621 A052031 this_sequence A105892 A111337 A162237
Adjacent sequences: A166006 A166007 A166008 this_sequence A166010 A166011 A166012
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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), Oct 04 2009
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EXTENSIONS
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1089 replaced by 1049 - R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Oct 05 2009
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