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A046930
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Size of sea of composite numbers surrounding n-th prime.
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7
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1, 1, 2, 4, 4, 4, 4, 4, 8, 6, 6, 8, 4, 4, 8, 10, 6, 6, 8, 4, 6, 8, 8, 12, 10, 4, 4, 4, 4, 16, 16, 8, 6, 10, 10, 6, 10, 8, 8, 10, 6, 10, 10, 4, 4, 12, 22, 14, 4, 4, 8, 6, 10, 14, 10, 10, 6, 6, 8, 4, 10, 22, 16, 4, 4, 16, 18, 14, 10, 4, 8, 12, 12, 10, 8, 8, 12, 10, 10, 16, 10, 10, 10, 6, 8, 8
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OFFSET
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1,3
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LINKS
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FORMULA
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EXAMPLE
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23 is in a sea of 8 composites: 20,21,22,23,24,25,26,27,28.
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MAPLE
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[ seq(ithprime(i)-ithprime(i-2)-2, i=3..100) ];
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MATHEMATICA
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Join[{1}, #[[3]]-#[[1]]-2&/@Partition[Prime[Range[90]], 3, 1]] (* Harvey P. Dale, Sep 26 2012 *)
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PROG
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(Haskell)
a046930 1 = 1
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CROSSREFS
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KEYWORD
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nonn,easy,nice
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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