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Search: id:A080357
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| A080357 |
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Smallest x such that between x and 2x exactly n twin prime numbers can be found. |
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+0
1
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| 2, 3, 36, 54, 90, 96, 99, 135, 174, 330, 411, 414, 516, 531, 546, 651, 714, 726, 741, 744, 804, 936, 939, 966, 975, 999, 1014, 1071, 1134, 1170, 1191, 1365, 1395, 1401, 1650, 1665, 1686, 1695, 1764, 1770, 1779, 1836, 1926, 2010, 2025, 2064, 2079, 2136, 2211
(list; graph; listen)
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OFFSET
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1,1
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FORMULA
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a(n)=Min[x; A080356(x)=n]
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EXAMPLE
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n=7: first seven twin primes counted between 99 and 198: {101,107,137,149,179,191,197}.
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MATHEMATICA
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f[x_] := Count[Table[PrimeQ[j]&&PrimeQ[j+2], {j, x, 2*x}], True] t=Table[0, {100}]; Do[s=f[n]; If[s<101&&t[[s]]==0, t[[s]]=n], {n, 1, 10000}]; t
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CROSSREFS
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Cf. A001359, A080356.
Sequence in context: A042663 A072291 A084191 this_sequence A064032 A118443 A109748
Adjacent sequences: A080354 A080355 A080356 this_sequence A080358 A080359 A080360
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KEYWORD
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nonn
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AUTHOR
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Labos E. (labos(AT)ana.sote.hu), Feb 19 2003
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