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A179835
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Smallest k > 0 such that prime(n-k) + prime(n+k) = 2*prime(n), or 0 if there is no such k.
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2
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0, 0, 1, 0, 2, 2, 2, 0, 0, 3, 3, 6, 3, 0, 0, 1, 7, 4, 8, 3, 0, 0, 7, 4, 6, 6, 2, 2, 0, 0, 6, 8, 7, 12, 0, 2, 1, 0, 6, 1, 2, 4, 8, 15, 15, 0, 1, 0, 0, 0, 6, 0, 0, 2, 1, 1, 0, 0, 6, 0, 0, 0, 19, 7, 0, 0, 17, 5, 29, 3, 15, 15, 5, 1, 5, 20, 20, 4, 7, 2, 21, 2, 21, 4, 3, 5, 4, 27, 3, 0, 0, 5, 28, 2, 0, 0, 0, 21, 0, 30
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OFFSET
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1,5
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LINKS
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MATHEMATICA
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nn=1000; p=Prime[Range[2*nn]]; Table[s=Take[p, n-1] + Reverse[Take[p, {n+1, 2n-1}]]; pos=Position[s, 2*p[[n]]]; If[pos=={}, 0, n-pos[[-1, 1]]], {n, nn}]
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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