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Search: id:A087378
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| A087378 |
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Smallest k such that both k-n and k+n are primes and there are no primes between them. |
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+0
1
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| 2, 4, 9, 26, 93, 144, 205, 120, 1839, 532, 897, 1140, 1681, 2490, 2985, 4312, 5607, 1344, 9569, 30612, 19353, 16162, 15705, 81486, 28253, 31932, 19635, 35644, 82101, 44322, 43361, 34092, 89721, 162176, 134547, 173394, 31433, 404634, 212739
(list; graph; listen)
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OFFSET
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0,1
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COMMENT
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For n>0, a(n) = arithmetic mean of the smallest pair of two consecutive primes with a difference 2n.
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FORMULA
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a(n) = A000230(n)+n. - David Wasserman (wasserma(AT)spawar.navy.mil), May 24 2005
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EXAMPLE
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a(5) = 144 as 139 and 149 both are prime and all numbers from 140 to 148 are composite.
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CROSSREFS
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Sequence in context: A127055 A124835 A125799 this_sequence A004252 A114957 A002773
Adjacent sequences: A087375 A087376 A087377 this_sequence A087379 A087380 A087381
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KEYWORD
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nonn
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AUTHOR
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Amarnath Murthy (amarnath_murthy(AT)yahoo.com), Sep 09 2003
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EXTENSIONS
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More terms from David Wasserman (wasserma(AT)spawar.navy.mil), May 24 2005
Edited by Franklin T. Adams-Watters (FrankTAW(AT)Netscape.net), Oct 26 2006
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