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Search: id:A106790
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| A106790 |
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Smallest k>0 such that binomial(n,k) + 1 is prime. |
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+0
1
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| 1, 1, 3, 1, 2, 1, 7, 2, 2, 1, 4, 1, 2, 5, 15, 1, 2, 1, 4, 2, 2, 1, 23, 2, 6, 4, 4, 1, 7, 1, 31, 10, 6, 10, 4, 1, 18, 15, 9, 1, 2, 1, 17, 2, 2, 1, 23, 2, 4, 20, 6, 1, 6, 8, 10, 6, 2, 1, 59, 1, 2, 25, 63, 2, 2, 1, 67, 8, 2, 1
(list; graph; listen)
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OFFSET
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1,3
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COMMENT
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a(n) <= n; for primes p: a(p-1) = 1.
The values of n for which a(n)=n yield the sequence A067317. - Emeric Deutsch (deutsch(AT)duke.poly.edu), Aug 27 2007
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MAPLE
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a:=proc(n) local k: for k while isprime(1+binomial(n, k))=false do end do: k end proc: seq(a(n), n=1..70); - Emeric Deutsch (deutsch(AT)duke.poly.edu), Aug 27 2007
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CROSSREFS
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Cf. A000040, A067317.
Adjacent sequences: A106787 A106788 A106789 this_sequence A106791 A106792 A106793
Sequence in context: A039620 A008296 A140185 this_sequence A078897 A011086 A103514
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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), May 16 2005
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EXTENSIONS
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Corrected and extended by Emeric Deutsch (deutsch(AT)duke.poly.edu), Aug 27 2007
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