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Search: id:A137811
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| A137811 |
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Number of digits in the n-th Woodall prime. |
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+0
1
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| 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
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OFFSET
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1,2
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COMMENT
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Woodall primes are prime numbers of the form n 2^n-1.
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REFERENCES
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Cunningham A. and Woodall, H. J.; Factorisation of Q=(2^q+-q) and (q 2^q+-1), Messenger Math. 47 (1917), pp.1-38.
Keller, Wilfred; New Cullen Primes, Mathematics of Computation, Vol. 64, No. 212. (Ocober 1995), pp. 1733-1741.
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LINKS
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Woodhall Primes, Definition And Status.
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FORMULA
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A055642(A050918(n))
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EXAMPLE
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As the sixth Woodall prime is a 27-digit number, we have a(6)= 27
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CROSSREFS
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Cf. A055642, A050918, A137716, A002234.
Sequence in context: A074496 A065849 A136402 this_sequence A041955 A157161 A041811
Adjacent sequences: A137808 A137809 A137810 this_sequence A137812 A137813 A137814
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KEYWORD
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base,hard,nonn
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AUTHOR
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Ant King (mathstutoring(AT)ntlworld.com), Feb 12 2008
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