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A099051
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p*2^p - 1 where p is prime.
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0
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7, 23, 159, 895, 22527, 106495, 2228223, 9961471, 192937983, 15569256447, 66571993087, 5085241278463, 90159953477631, 378231999954943, 6614661952700415, 477381560501272575, 34011184385901985791
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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COMMENTS
| 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
| Ribenboim, P. The New Book of Prime Number Records. New York: Springer-Verlag, pp. 360-361, 1996
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LINKS
| Eric Weisstein's World of Mathematics, Woodall Numbers.
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EXAMPLE
| If p=3, 3*2^3 - 1 = 23
If p=11, 11*2^11 - 1 = 22527
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MATHEMATICA
| 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
| Similar to Woodall numbers (A003261). Cf. A002234.
Sequence in context: A080082 A158954 A056205 * A187487 A034192 A050918
Adjacent sequences: A099048 A099049 A099050 * A099052 A099053 A099054
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KEYWORD
| nonn,easy
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AUTHOR
| Parthasarathy Nambi (PachaNambi(AT)yahoo.com), Nov 13 2004
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EXTENSIONS
| More terms from Robert G. Wilson v (rgwv(AT)rgwv.com), Nov 15 2004
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