login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 59th year, we have over 358,000 sequences, and we’ve crossed 10,300 citations (which often say “discovered thanks to the OEIS”).

Other ways to Give
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A077085 Initial values such that if A077080(x)=phi(sigma(x)+phi(x)) is started at these numbers then the sequence does not converge. 6
534, 556, 557, 580, 624, 702, 710, 738, 739, 740, 748, 784, 789, 822, 823, 841, 852, 853, 900, 912, 913, 916, 924, 931, 938, 960, 961, 962, 1020, 1021, 1029, 1032, 1033, 1034, 1065, 1089, 1092, 1093, 1098, 1126, 1136 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

These terms are only conjectures.

LINKS

Table of n, a(n) for n=1..41.

MATHEMATICA

f[x_] := EulerPhi[DivisorSigma[1, x]+EulerPhi[x]] Do[s=Part[NestList[f, n, 100], 100]; If[Greater[s, 10000000], Print[{n, s}]], {n, 1, 10000}]

CROSSREFS

Cf. A000010, A000203, A065387, A077080-A077085.

Sequence in context: A067803 A098258 A160176 * A165989 A183598 A252536

Adjacent sequences: A077082 A077083 A077084 * A077086 A077087 A077088

KEYWORD

nonn

AUTHOR

Labos Elemer, Oct 28 2002

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified December 6 18:39 EST 2022. Contains 358644 sequences. (Running on oeis4.)