

A099051


p*2^p  1 where p is prime.


0



7, 23, 159, 895, 22527, 106495, 2228223, 9961471, 192937983, 15569256447, 66571993087, 5085241278463, 90159953477631, 378231999954943, 6614661952700415, 477381560501272575, 34011184385901985791
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OFFSET

1,1


COMMENTS

This is the subset of Woodall numbers of prime index. The 9th largest known Woodall prime is in this sequence: 12379*2^123791, 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, Nov 19 2004


REFERENCES

Ribenboim, P. The New Book of Prime Number Records. New York: SpringerVerlag, pp. 360361, 1996


LINKS

Table of n, a(n) for n=1..17.
Eric Weisstein's World of Mathematics, Woodall Numbers.


EXAMPLE

If p=3, 3*2^3  1 = 23.
If p=11, 11*2^11  1 = 22527.


MATHEMATICA

Table[ Prime[n]*2^Prime[n]  1, {n, 17}] (* Robert G. Wilson v, Nov 16 2004 *)


CROSSREFS

Similar to Woodall numbers (A003261). Cf. A002234.
Sequence in context: A080082 A158954 A056205 * A187487 A299643 A034192
Adjacent sequences: A099048 A099049 A099050 * A099052 A099053 A099054


KEYWORD

nonn,easy


AUTHOR

Parthasarathy Nambi, Nov 13 2004


EXTENSIONS

More terms from Robert G. Wilson v, Nov 15 2004


STATUS

approved



