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Search: id:A109835
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| A109835 |
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Primes connected to two primes by the (p+1)/2 and 2p-1 operators. |
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4
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| 3, 37, 157, 661, 877, 997, 1237, 1657, 2137, 2557, 3061, 4177, 4261, 4357, 4621, 5581, 6037, 6121, 6217, 6361, 7537, 8317, 8461, 8521, 9241, 9277, 9721, 9901, 10837, 11497, 12241, 12421, 13417, 13681, 14737, 14821, 15121, 15277, 16417, 17257
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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Primes involved in Cunningham chains of the second kind (2p-1) and not starting or ending them. A059455 is produced by the same rule, but "of the first kind (2p+1)"
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LINKS
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Chris Caldwell's Prime Glossary, Cunningham chains.
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EXAMPLE
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a(2)=37 is here because (37+1)/2=19 and (2*37)-1=73 are both primes;
a(11)=3061 because 1531->3061->6121 through <2p-1> and all primes;
a(11)=3061, a(18)=6121, and a(31)=12241 are here because they are "in" the complete Cunningham chain of the second kind 1531->3061->6121->12241->24481
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CROSSREFS
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Cf. A059455, A005385.
Adjacent sequences: A109832 A109833 A109834 this_sequence A109836 A109837 A109838
Sequence in context: A030460 A041067 A046867 this_sequence A066364 A106995 A120076
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KEYWORD
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nonn
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AUTHOR
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Alexandre Wajnberg (alexandre.wajnberg(AT)ulb.ac.be), Aug 31 2005
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