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A087779
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a(n)=prime(x) is the smallest prime such that 1+(2^(12n+9))*prime(x) is divisible by prime(x+1).
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0
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19, 43, 67, 31, 2087, 29, 31, 89, 6359, 31, 29, 19, 31, 199, 1429, 29, 229, 641, 31, 41, 29, 31, 19, 89, 31, 29, 41, 31, 29573, 38729, 29, 89, 389, 19, 43103, 29, 31, 67, 929, 31, 29, 38729, 31, 89, 19, 29, 146543, 41, 31, 1193, 29, 31, 5077, 53, 31, 19, 449, 31, 701
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,1
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FORMULA
| a(n)=Min{p[x]; Mod[1+[2^(12n+9)].p[x], p[x+1]]=0}; a(n)=A087985[2^(9+12n)]
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EXAMPLE
| n = 4: exponent = 4.12+9 = 57, 2^57 = 144115188075855872; a(4) = 2087 = p[315] because 1+144115188075855872.2087 = 300768397514311204865 = 2089.5.23.2593.14669.32914927 = p[316].m
Must a solution always exist? Difficult exponents are 193,253,...
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CROSSREFS
| Cf. A087985.
Sequence in context: A162856 A095086 A095079 * A106950 A141438 A095103
Adjacent sequences: A087776 A087777 A087778 * A087780 A087781 A087782
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KEYWORD
| nonn
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AUTHOR
| Labos E. (labos(AT)ana.sote.hu), Oct 06 2003
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EXTENSIONS
| More terms from David Wasserman (wasserma(AT)spawar.navy.mil), Jun 17 2005
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