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Search: id:A109946
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| A109946 |
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Smallest prime starting a complete two iterations Cunningham chain of the first and second kind. |
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4
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| 2, 19, 41, 79, 331, 439, 499, 619, 829, 1031, 1069, 1279, 1451, 1481, 1511, 1811, 1889, 1901, 1931, 2089, 2179, 2791, 3019, 3109, 3181, 3449, 3491, 3769, 3821, 3911, 4159, 4231, 4639, 4861, 4951, 5081, 5419, 5441, 5749, 5849, 6101, 6131, 6709, 7151, 7349
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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Intersection of A057326 and A059762. The terms have to start a chain through iteration by either <2p+1> or <2p-1> operator (not mixed in the same chain); and the chains has to be three primes long.
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LINKS
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Chris Caldwell, The Prime Glossary, Cunningham chains.
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EXAMPLE
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a(1)=2 is here because 2 -> 3 -> 5 through <2p-1> and the chain ends here (with this operator).
a(2)=19 is here because 19 -> 37 -> 73 through <2p-1>.
a(3)=41 is here because 41 -> 83 -> 167 through <2p+1>.
- 11 is not here because it is well followed by two terms, but doesn't start this sequence (2->5->11->23->47).
- 89 is not here because it starts a 6 terms chain.
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MAPLE
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Terms computed by Gilles Sadowski.
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CROSSREFS
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Cf. A057326, A059762.
Sequence in context: A018610 A075682 A062587 this_sequence A140560 A031911 A136685
Adjacent sequences: A109943 A109944 A109945 this_sequence A109947 A109948 A109949
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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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