

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
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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



