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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
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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; refs; listen; history; internal format)
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OFFSET
| 0,1
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COMMENTS
| For n>0, a(n) = arithmetic mean of the smallest pair of two consecutive primes with a difference 2n.
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FORMULA
| a(n) = A000230(n)+n. - David Wasserman (wasserma(AT)spawar.navy.mil), May 24 2005
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EXAMPLE
| a(5) = 144 as 139 and 149 both are prime and all numbers from 140 to 148 are composite.
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CROSSREFS
| Sequence in context: A124835 A125799 A188669 * A004252 A114957 A002773
Adjacent sequences: A087375 A087376 A087377 * A087379 A087380 A087381
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KEYWORD
| nonn
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AUTHOR
| Amarnath Murthy (amarnath_murthy(AT)yahoo.com), Sep 09 2003
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EXTENSIONS
| 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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