A077093 Smallest initial values leading to fixed points listed in A077092.

1, 4, 24, 7530, 12100, 32784, 34950, 69480, 121104, 420096, 1018980, 2846484, 2946560, 4160040, 5387484, 5512800, 5729520, 13108800, 23524452, 24799080, 25885760, 31382952, 53344272, 100929036, 150057300, 352636452

Offset

1,2

Links

Table of n, a(n) for n=1..26.

Example

n=12100: FixedPointList={12100,24000,34944},end=34944; n=121104: FixedPointList={121104,268560}, end=268560.

Mathematica

f[x_] := EulerPhi[DivisorSigma[1, x]-EulerPhi[x]]; Do[s=NestList[f, n, 100]; s1=Part[s, 99]; s2=Part[s, 100]; If[Equal[s1, s2]&&!PrimeQ[n], Print[{n, s1}]], {n, 1, 1000}] (*n=site if fixed point appears; s1=fixed point*)

Crossrefs

Cf. A077090, A077091, A077092, A077094, A077095, A077096, A077099, A077100.

Sequence in context: A065711 A279240 A279110 * A077092 A092435 A058230

Adjacent sequences: A077090 A077091 A077092 * A077094 A077095 A077096

Keyword

nonn,more

Author

Labos Elemer, Oct 31 2002

Extensions

a(11)-a(26) from Sean A. Irvine, May 06 2025

Status

approved