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Search: id:A159687
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| A159687 |
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Number of strong primes < 10^n. |
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+0
1
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| 0, 10, 73, 574, 4543, 37723, 320991, 2796946, 24758534, 222126290, 201400162
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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The number of strong primes < n ~ sum of strong primes < sqrt(n). The number
of strong primes < 10^11 = 2014200162 and the sum of strong primes < 10^5.5
= 1972716560, for an error of 0.0206.
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LINKS
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Cino Hilliard, Sum of Strong Primes
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FORMULA
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Given 3 consecutive primes p1,p2,p3, p2 is a strong prime if p2 > (p1+p2)/2.
Or, primes that are greater than the arithmetic mean of their immediate
surrounding primes.
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EXAMPLE
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The strong primes < 10^2 are 11,17,29,37,41,59,67,71,79,97. These add up
to 10 which is the second term in the sequence.
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PROGRAM
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(Other) See the link for Gcc programs that count and sum these primes.
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CROSSREFS
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Sequence in context: A161743 A016211 A055424 this_sequence A044197 A044578 A103434
Adjacent sequences: A159684 A159685 A159686 this_sequence A159688 A159689 A159690
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KEYWORD
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nonn
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AUTHOR
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Cino Hilliard (hillcino368(AT)hotmail.com), Apr 19 2009
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EXTENSIONS
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Edited by N. J. A. Sloane, Apr 20 2009
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