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Search: id:A144043
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| A144043 |
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Sum of the middle pair as the prime sequence unfolds |
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+0
1
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| 2, 3, 4, 5, 6, 8, 10, 12, 14, 18, 22, 24, 26, 30, 34, 36, 38, 42, 46
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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An exotic sequence with a tantalizing non-regularity. It is strictly nondecreasing (very easy to show). The first order differences (1, 1, 1, 1, 2, 2, 2, 2, 4, 4, 2, 2, 4, 4, 2, 2, 4, 4, ...) are also very erratic.
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EXAMPLE
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2= sumtwice(1) 3= sum(1,2) 4= 1, sumtwice(2), 3 5= 1, sum(2,3), 5 6= 1, 2, sumtwice(3), 5, 7 8= 1,2, sum(3,5), 7, 11
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PROGRAM
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(Other) %Matlab source code clc clear all aP= [1, primes(1000)]; qN= numel(aP); kL=[]; %init empty result for nn= 1:qN %Loop to sum the central pairs auxT= ceil((nn+1)/2); auxL= ceil(nn/2); kL= [kL; aP(auxL)+aP(auxT)]; end kL %kL is the result
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CROSSREFS
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Sequence in context: A056864 A029032 A059809 this_sequence A121492 A078931 A003401
Adjacent sequences: A144040 A144041 A144042 this_sequence A144044 A144045 A144046
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KEYWORD
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easy,nonn
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AUTHOR
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Raul Rato (rtrato(AT)yahoo.com), Sep 08 2008
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