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Search: id:A098429
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| A098429 |
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Number of cousin prime pairs (p, p+4) with p <= n. |
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+0
4
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| 0, 0, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 5, 5, 5, 5, 5, 5, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 9, 9, 9, 9, 9, 9, 10, 10
(list; graph; listen)
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OFFSET
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1,7
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COMMENT
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Convention: a prime pair is <= n iff its smallest member is <= n.
Except for (3, 7), there is only 1 pair congruence class for cousin primes, i.e. (+1, -1) (mod 6). [From Daniel Forgues (squid(AT)zensearch.com), Aug 05 2009]
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LINKS
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Daniel Forgues, Table of n, a(n) for n=1..99996
Eric Weisstein's World of Mathematics, Cousin Primes
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EXAMPLE
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First cousin prime pairs: (3,7),(7,11),(13,17),(19,23), ...
therefore the sequence starts: 0 0 1 1 1 1 2 2 2 2 2 2 3 ...
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CROSSREFS
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Cf. A023200, A046132, A098428, A071538.
Sequence in context: A132085 A111654 A067099 this_sequence A132090 A071538 A138194
Adjacent sequences: A098426 A098427 A098428 this_sequence A098430 A098431 A098432
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KEYWORD
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nonn
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AUTHOR
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Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Sep 07 2004
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EXTENSIONS
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Edited by Daniel Forgues (squid(AT)zensearch.com), Aug 01 2009
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