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A046929
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Width of moat of composite numbers surrounding n-th prime.
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18
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0, 0, 1, 1, 1, 1, 1, 1, 3, 1, 1, 3, 1, 1, 3, 5, 1, 1, 3, 1, 1, 3, 3, 5, 3, 1, 1, 1, 1, 3, 3, 3, 1, 1, 1, 1, 5, 3, 3, 5, 1, 1, 1, 1, 1, 1, 11, 3, 1, 1, 3, 1, 1, 5, 5, 5, 1, 1, 3, 1, 1, 9, 3, 1, 1, 3, 5, 5, 1, 1, 3, 5, 5, 5, 3, 3, 5, 3, 3, 7, 1, 1, 1, 1, 3, 3, 5, 3, 1, 1, 3, 7, 3, 3
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OFFSET
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1,9
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LINKS
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EXAMPLE
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23 has a buffer of 3 composites around it on each side: 20,21,22,23,24,25,26.
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MAPLE
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with(numtheory); a := i->min(ithprime(n)-ithprime(n-1)-1, ithprime(n+1)-ithprime(n)-1);
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MATHEMATICA
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a[n_] := Min[Prime[n] - Prime[n-1] - 1, Prime[n+1] - Prime[n] - 1]; a[1] = 0; Table[a[n], {n, 1, 100}] (* Jean-François Alcover, Apr 16 2013 *)
Join[{0}, Min[Differences[#]]&/@Partition[Prime[Range[100]], 3, 1]-1] (* Harvey P. Dale, Feb 24 2014 *)
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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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STATUS
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approved
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