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A137811 Number of digits in the n-th Woodall prime. 0
1, 2, 3, 11, 25, 27, 37, 40, 78, 112, 119, 142, 157, 229, 251, 1603, 2339, 2874, 3731, 4768, 5690, 6920, 6930, 29725, 43058, 45468, 200815 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Woodall primes are prime numbers of the form n*2^n-1.

REFERENCES

A. Cunningham and H. J. Woodall, Factorisation of Q=(2^q+-q) and (q 2^q+-1), Messenger Math. 47 (1917), pp. 1-38.

Wilfrid Keller, New Cullen Primes, Mathematics of Computation, Vol. 64, No. 212 (Ocober 1995), pp. 1733-1741.

LINKS

Table of n, a(n) for n=1..27.

Woodhall Primes, Definition And Status.

FORMULA

A055642(A050918(n))

EXAMPLE

As the sixth Woodall prime is a 27-digit number, we have a(6)= 27

CROSSREFS

Cf. A055642, A050918, A137716, A002234.

Sequence in context: A292112 A065849 A136402 * A041955 A239445 A157161

Adjacent sequences:  A137808 A137809 A137810 * A137812 A137813 A137814

KEYWORD

base,hard,nonn

AUTHOR

Ant King, Feb 12 2008

STATUS

approved

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Last modified May 17 04:28 EDT 2022. Contains 353730 sequences. (Running on oeis4.)