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Search: id:A070018
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| A070018 |
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a(n) = smallest prime p = prime(k) such that gcd( prime(k+1) - prime(k), prime(k+2) - prime(k+1) ) = 2n. |
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+0
2
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| 3, 89, 47, 1823, 1627, 199, 5939, 5591, 15823, 83117, 259033, 16763, 365851, 1074167, 69593, 1625027, 2541289, 255767, 11772613, 3312227, 247099, 3565931
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OFFSET
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1,1
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FORMULA
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a(n)=Min{x : A057467(x)=2n}.
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EXAMPLE
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n=21: a(21)=247099, the consecutive prime triple {247099,247141,247183} determines {42,42} successive differences, the GCD of which is 2n=42.
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MATHEMATICA
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f[x_] := GCD[Prime[x+1]-Prime[x], Prime[x+2]-Prime[x+1]]; t = Table[0, {256} ]; Do[ c = f[n]; If[c <257 && t[[b]] == 0, t[[c]] = n], {n, 2, 1000000} ]; t Prime[t]
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CROSSREFS
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Cf. A001223, A057467. Different from A054682
Sequence in context: A037112 A093748 A156737 this_sequence A054682 A106944 A142252
Adjacent sequences: A070015 A070016 A070017 this_sequence A070019 A070020 A070021
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KEYWORD
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nonn,more
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AUTHOR
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Labos E. (labos(AT)ana.sote.hu) and Benoit Cloitre (benoit7848c(AT)orange.fr), Apr 12 2002
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