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A115061 a(n) is the number of occurrences of the n-th prime number in A051697. 3
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 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

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

LINKS

Nathaniel Johnston, Table of n, a(n) for n = 1..10000

FORMULA

a(n) = (prime(n+1) - prime(n-1))/2 for n>=3. - Nathaniel Johnston, Jun 25 2011

EXAMPLE

The 5th prime number, 11, appears three times in A051697. Therefore a(5) = 3.

MATHEMATICA

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

CROSSREFS

Sequence in context: A069901 A115039 A032536 * A217834 A227877 A225867

Adjacent sequences:  A115058 A115059 A115060 * A115062 A115063 A115064

KEYWORD

nonn,easy

AUTHOR

Lekraj Beedassy, Mar 01 2006

EXTENSIONS

Edited and extended by Stefan Steinerberger, Oct 27 2007

STATUS

approved

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Last modified December 14 22:42 EST 2019. Contains 329987 sequences. (Running on oeis4.)