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A060611
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Smallest prime p such that n = A049108(p) = length of chain of iterates of Euler Phi starting with p.
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4
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2, 3, 5, 11, 17, 41, 83, 137, 257, 641, 1097, 2657, 5441, 10883, 17477, 40961, 65537, 140417, 295937, 557057, 1193537, 2384897, 4227137, 9548417, 17966357, 35946497, 71304257, 162174977, 305268737, 541073537, 1212153857, 2281701377
(list; graph; refs; listen; history; internal format)
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OFFSET
| 2,1
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COMMENTS
| From 2nd to 12th term A007755 is the same as this sequence
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LINKS
| T. D. Noe, Table of n, a(n) for n=2..1002
Project Euler, Problem 214: Totient chains.
T. D. Noe, Computing Numbers in Section I of the Totient Iteration [From T. D. Noe (noe(AT)sspectra.com), Nov 18 2008]
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EXAMPLE
| n=13: a(13)=2657 is the smallest prime which gives a chain of length 13, 2657 -> 2656 -> 1312 -> 640 -> 256 -> 128 -> 64 -> 32 -> 16 -> 8 -> 4 -> 2 -> 1, while the smallest number having this property is A007755(13) = 2329 -> 2176 -> 1024 -> 512 -> 256 -> 128 -> 64 -> 32 -> 16 -> 8 -> 4 -> 2 -> 1.
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CROSSREFS
| Cf. A000010, A049108 = A003434 + 1, A007755, A049117.
Sequence in context: A085613 A082605 A007755 * A103598 A077497 A178606
Adjacent sequences: A060608 A060609 A060610 * A060612 A060613 A060614
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KEYWORD
| nonn
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AUTHOR
| Labos E. (labos(AT)ana.sote.hu), Apr 13 2001
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EXTENSIONS
| More terms from Jud McCranie (JudMcCranie(AT)ugaalum.uga.edu), Apr 22 2001
Removed duplicate cross references, added link, reformulated example. - M. F. Hasler (www.univ-ag.fr/~mhasler), Oct 25 2008
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