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Search: id:A105470
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| A105470 |
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a(n)=1 if there is number of the form 6k+3 with prime(n) <= 6k+3 <= prime(n+1), otherwise 0. |
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+0
1
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| 1, 1, 0, 1, 0, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 1, 0, 1, 1, 0, 1, 1, 1, 1, 1, 0, 1, 0, 1, 1, 1, 1, 0, 1, 0, 1, 1, 1, 1, 1, 0, 1, 0, 1, 0, 1, 1, 1, 0, 1, 1, 0, 1, 1, 1, 1, 0, 1, 1, 0, 1, 1, 1, 0, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 0, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 0, 1
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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Except for the first pair of primes and for twin primes there is always at least one number of the form 6n+3 between two successive primes.
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EXAMPLE
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a(3)=0 because between prime(3) and prime(4) there are no numbers of the form 6k+3;
a(4)=1 because between prime(4) and prime(5) there is one number of the form 6k+3: 9.
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MATHEMATICA
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f[n_] := Count[Table[Mod[k, 6], {k, Prime[n], Prime[n + 1]}], 3]; Table[If[f[n] == 0, 0, 1], {n, 120}] (*Chandler*)
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CROSSREFS
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Cf. A100810, A106002.
Sequence in context: A135528 A071040 A078387 this_sequence A087429 A093075 A104120
Adjacent sequences: A105467 A105468 A105469 this_sequence A105471 A105472 A105473
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KEYWORD
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easy,nonn
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AUTHOR
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Giovanni Teofilatto (g.teofilatto(AT)tiscalinet.it), May 02 2005
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EXTENSIONS
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Edited by Ray Chandler (rayjchandler(AT)sbcglobal.net), Oct 17 2006
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