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Search: id:A075051
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| A075051 |
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Smallest prime for which the n closest primes are smaller. |
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+0
8
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| 3, 113, 113, 113, 1327, 1327, 15683, 15683, 248909, 265621, 492113, 492113, 3851459, 7743233, 18640103, 18640103, 18640103, 435917249, 435917249, 435917249, 649580171, 649580171, 19187736221, 19187736221, 19187736221, 94746870541, 94746870541, 673420121333, 1975675658371
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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It is surprising that few of the above entries are in prime gaps (A000230) or (A002386).
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EXAMPLE
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The smallest prime number for which the three closest primes to itself are all smaller than itself is 113 (the closest primes being 109, 107, and 103). So a(3)=113.
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MATHEMATICA
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NextPrim[n_] := Block[{k = n + 1}, While[ !PrimeQ[k], k++ ]; k]; PrevPrim[n_] := Block[{k = n - 1}, While[ !PrimeQ[k], k-- ]; k]; k = 1; Do[ps = Table[0, {n + 1}]; ps = Append[ps, Max[k, 1]]; While[ps = Drop[ps, 1]; ps = Append[ps, NextPrim[ ps[[ -1]]]]; ps[[ -1]] - ps[[ -2]] <= ps[[ -2]] - ps[[1]], ]; Print[ ps[[ -2]]]; k = PrevPrim[ ps[[1]]], {n, 1, 30}]
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CROSSREFS
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Cf. A001223, A074979, A074982, A075030, A075037, A075038, A075043 & A075050.
Sequence in context: A037116 A054330 A024043 this_sequence A139929 A142603 A065117
Adjacent sequences: A075048 A075049 A075050 this_sequence A075052 A075053 A075054
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KEYWORD
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nonn
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AUTHOR
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N. Fernandez (primeness(AT)borve.org), Oct 10 2002
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EXTENSIONS
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Edited and extended by Robert G. Wilson v (rgwv(AT)rgwv.com), Oct 12 2002
a(23)-a(29) from Donovan Johnson (donovan.johnson(AT)yahoo.com), Jun 19 2008
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