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A060611 Smallest prime p such that n = A049108(p) = length of chain of iterates of Euler Phi starting with p. 4
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; text; internal format)
OFFSET

2,1

COMMENTS

From 2nd to 12th term A007755 is the same as this sequence

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

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.

CROSSREFS

Cf. A000010, A049108 = A003434 + 1, A007755, A049117.

A007755 has the same initial terms but is a different sequence.

Sequence in context: A085613 A082605 A007755 * A077497 A237995 A178606

Adjacent sequences:  A060608 A060609 A060610 * A060612 A060613 A060614

KEYWORD

nonn

AUTHOR

Labos Elemer, Apr 13 2001

EXTENSIONS

More terms from Jud McCranie, Apr 22 2001

Removed duplicate cross references, added link, reformulated example. - M. F. Hasler, Oct 25 2008

STATUS

approved

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Last modified March 26 04:32 EDT 2019. Contains 321481 sequences. (Running on oeis4.)