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A115061
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a(n) is the number of occurrences of the n-th prime number in A051697.
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3
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3, 2, 2, 3, 3, 3, 3, 3, 5, 4, 4, 5, 3, 3, 5, 6, 4, 4, 5, 3, 4, 5, 5, 7, 6, 3, 3, 3, 3, 9, 9, 5, 4, 6, 6, 4, 6, 5, 5, 6, 4, 6, 6, 3, 3, 7, 12, 8, 3, 3, 5, 4, 6, 8, 6, 6, 4, 4, 5, 3, 6, 12, 9, 3, 3, 9, 10, 8, 6, 3, 5, 7, 7, 6, 5, 5, 7, 6, 6
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OFFSET
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1,1
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COMMENTS
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Except for the second entry, the sequence also holds with respect to A077018.
a(n) equals A162345(n) for n>1 and equals A052288(n-2) for n>2. - Nathaniel Johnston, Jun 25 2011
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LINKS
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Nathaniel Johnston, Table of n, a(n) for n = 1..10000
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FORMULA
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a(n) = (prime(n+1) - prime(n-1))/2 for n>=3. - Nathaniel Johnston, Jun 25 2011
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EXAMPLE
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The 5th prime number, 11, appears three times in A051697. Therefore a(5) = 3.
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MATHEMATICA
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a = {3}; For[n = 2, n < 100, n++, c = 0; For[j = Prime[n - 1], j < Prime[n + 1], j++, If[j < Prime[n], If[Prime[n] - j < j - Prime[n - 1], c++ ], If[Not[Prime[n + 1] - j < j - Prime[n]], c++ ]]]; AppendTo[a, c]]; a
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CROSSREFS
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Sequence in context: A069901 A115039 A032536 * A217834 A046822 A129001
Adjacent sequences: A115058 A115059 A115060 * A115062 A115063 A115064
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KEYWORD
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nonn,easy
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AUTHOR
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Lekraj Beedassy, Mar 01 2006
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EXTENSIONS
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Edited and extended by Stefan Steinerberger, Oct 27 2007
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STATUS
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approved
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