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Search: id:A153167
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| A153167 |
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Numbers n such that n+2 is not a Chen prime |
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+0
2
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| 2, 4, 6, 7, 8, 10, 12, 13, 14, 16, 18, 19, 20, 22, 23, 24, 25, 26, 28, 30, 31, 32, 33, 34, 36, 37, 38, 40, 41, 42, 43, 44, 46, 47, 48, 49, 50, 52, 53, 54, 55, 56, 58, 59, 60, 61, 62, 63, 64, 66, 67, 68, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 82, 83, 84, 85, 86, 88, 89, 90
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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Contains all strictly positive even numbers A005843.
For each odd k>1 we can accumulate the numbers == k^2-2 (mod 2k) in a row,
the last entry equal to A073577(k):
7; (k=3)
13, 23; (k=5)
19, 33, 47; (k=7)
25, 43, 61, 79; (k=9)
31, 53, 75, 97, 119; (k=11)
7, 63, 89, 115, 141, 167; (k=13)
43, 73, 103, 133, 163, 193,223; (k=17)
49, 83, 17, 151,185, 219, 253, 287; (k=19)
Each element T of the this table has the format T= k^2-2-j*2*k, so T+2 is of
the form k*(k-2*j), therefore not prime, and consequently all elements T are in the sequence.
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CROSSREFS
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Cf. A109611, A040976, A073577, A067076.
Sequence in context: A080645 A024413 A153347 this_sequence A047237 A039028 A153282
Adjacent sequences: A153164 A153165 A153166 this_sequence A153168 A153169 A153170
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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), Dec 20 2008
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EXTENSIONS
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Edited, 41, 59 (see A102540) etc inserted by R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Oct 16 2009
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