login
This site is supported by donations to The OEIS Foundation.
Logo

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A097002 A062402(x)=sigma(phi[x]) function is iterated; initial value=2^n; a(n)=smallest term of trajectory. 0
1, 3, 7, 15, 31, 63, 127, 255, 511, 1023, 2047, 4095, 8191, 6045, 24552, 65535, 131071, 262143, 524287, 1048575, 2097151, 4194303, 8388607, 16777215, 33554431, 67108863, 134217727, 268435455, 536870911, 1073741823 (list; graph; refs; listen; history; internal format)
OFFSET

1,2

EXAMPLE

n=13: 2^n=8192, trajectory ={8192, 8191, 26208, [20440], 20440, .. a[13]=8191 arose in transient.

MATHEMATICA

gf[x_] :=DivisorSigma[1, EulerPhi[x]] gite[x_, hos_] :=NestList[gf, x, hos] Table[Min[gite[2^w, 200]], {w, 1, 30}]

CROSSREFS

Cf. A000010, A000203, A062402, A096857.

Sequence in context: A043755 A105755 A043764 * A060152 A168604 A126646

Adjacent sequences:  A096999 A097000 A097001 * A097003 A097004 A097005

KEYWORD

nonn

AUTHOR

Labos E. (labos(AT)ana.sote.hu), Jul 21 2004

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Transforms | Puzzles | Hot | Classics
Recent Additions | More pages | Superseeker | Maintained by The OEIS Foundation Inc.

Content is available under The OEIS End-User License Agreement .

Last modified February 17 11:18 EST 2012. Contains 206011 sequences.