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Search: id:A143738
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| A143738 |
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Number of twin primes between n and n^2. Only smaller of twins (terms of A001359) are counted. |
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+0
1
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| 0, 1, 2, 2, 3, 3, 4, 5, 6, 6, 8, 8, 9, 11, 12, 14, 16, 16, 17, 17, 19, 20, 21, 22, 24, 26, 26, 26, 29, 30, 30, 31, 34, 36, 36, 39, 41, 42, 45, 45, 48, 49, 50, 53, 55, 59, 61, 63, 66, 66, 68, 70, 74, 74, 76, 77, 78, 83, 87, 90, 91, 93, 96, 100
(list; graph; listen)
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OFFSET
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1,3
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EXAMPLE
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For n=6, between 6 and 36 the twin numbers are {11,17,29}, so a(6)=3.
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MATHEMATICA
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Table[Count[Table[PrimeQ[j] && PrimeQ[j + 2], {j, n, n*n}], True], {n, 1, 100}]
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CROSSREFS
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A001359, A080356
Sequence in context: A097330 A086861 A113865 this_sequence A029071 A117144 A104408
Adjacent sequences: A143735 A143736 A143737 this_sequence A143739 A143740 A143741
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KEYWORD
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nonn
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AUTHOR
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Alen Skugor (askugor(AT)gmail.com), Aug 30 2008
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