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A051918
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Start with n, apply k->2k+1 until reach new record prime; sequence gives number of steps needed.
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1
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2, 2, 2, 3, 4, 5, 5, 10, 13, 13, 26, 32, 287, 18380, 21727, 23205, 24828, 35646, 48819, 51476
(list;
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OFFSET
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0,1
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COMMENTS
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a(20) > 60000. [From Donovan Johnson, May 23 2010]
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LINKS
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Table of n, a(n) for n=0..19.
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EXAMPLE
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0->1->3, new record prime 3 in 2 steps; 1->3->7, new record prime 7 in 2 steps; 2->5->11, new record prime 11 in 2 steps; 3->7->15->31, new record prime 31 in 3 steps.
For the next few terms we have: 4->9->19->39->79; 5->11->23->47->95->191; 6->13->27->55->111->223; 7->15->31->63->127->255->511->1023->2047->4095->8191; etc.
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CROSSREFS
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Cf. A051919, A052333.
Sequence in context: A008906 A029074 A036016 * A174740 A163801 A029049
Adjacent sequences: A051915 A051916 A051917 * A051919 A051920 A051921
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KEYWORD
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nice,nonn,hard
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AUTHOR
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N. J. A. Sloane, Dec 18 1999
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EXTENSIONS
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More terms from Naohiro Nomoto, May 21 2001
a(13)-a(19) from Donovan Johnson, May 23 2010
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STATUS
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approved
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