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Search: id:A099051
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| A099051 |
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p*2^p - 1 where p is prime. |
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+0
1
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| 7, 23, 159, 895, 22527, 106495, 2228223, 9961471, 192937983, 15569256447, 66571993087, 5085241278463, 90159953477631, 378231999954943, 6614661952700415, 477381560501272575, 34011184385901985791
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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This is the subset of Woodall numbers of prime index. The 9th largest known Woodall prime is in this sequence: 12379*2^12379-1, where 12379 is prime, as found by Wilfrid Keller in 1984. Smaller primes are when p = 2, 3, 751. These numbers can also be semiprime, as when p = 159, 163, or 211 and hard to factor as when n = 349 (108 digits). - Jonathan Vos Post (jvospost3(AT)gmail.com), Nov 19 2004
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REFERENCES
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Ribenboim, P. The New Book of Prime Number Records. New York: Springer-Verlag, pp. 360-361, 1996
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LINKS
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Eric Weisstein's World of Mathematics, Woodall Numbers.
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EXAMPLE
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If p=3, 3*2^3 - 1 = 23
If p=11, 11*2^11 - 1 = 22527
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MATHEMATICA
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Table[ Prime[n]*2^Prime[n] - 1, {n, 17}] (from Robert G. Wilson v (rgwv(AT)rgwv.com), Nov 16 2004)
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CROSSREFS
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Similar to Woodall numbers (A003261). Cf. A002234.
Sequence in context: A080082 A158954 A056205 this_sequence A034192 A050918 A159485
Adjacent sequences: A099048 A099049 A099050 this_sequence A099052 A099053 A099054
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KEYWORD
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nonn,easy
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AUTHOR
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Parthasarathy Nambi (PachaNambi(AT)yahoo.com), Nov 13 2004
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EXTENSIONS
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More terms from Robert G. Wilson v (rgwv(AT)rgwv.com), Nov 15 2004
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