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Search: id:A096831
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| A096831 |
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Number of primes in the neighborhood with center = n-th-primorial and radius = Ceiling[Log[n-th-primorial]]. |
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+0
2
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| 2, 2, 2, 1, 2, 1, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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What is exceptional in such neighborhoods of primorials, that in most cases no primes occur, i.e. these zones are peculiarly poor or empty of primes!
Primes are scarce in these zones because log(A002110(n)) < prime(n), so A002110(n)+1 and A002110(n)-1 are the only numbers in the neighborhood that are not divisible by one of the first n primes. - David Wasserman (dwasserm(AT)earthlink.net), Nov 16 2007
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FORMULA
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a[n]=A096509[A002110(n)]
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EXAMPLE
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n=7,7th/primorial=510510,radius=14,a[7]=0 because no primes in the relevant neighborhood;
Only [1, 3], [4, 8], [26, 34], [2302, 2318] are those zones around 2, 6, 30, 2310 respectively in which 2 primes were found.
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CROSSREFS
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Cf. A096509-A096523, A002110.
Sequence in context: A089722 A079562 A129320 this_sequence A034095 A105971 A080354
Adjacent sequences: A096828 A096829 A096830 this_sequence A096832 A096833 A096834
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KEYWORD
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nonn
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AUTHOR
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Labos E. (labos(AT)ana.sote.hu), Jul 14 2004
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