A077085 Initial values such that if A077080(x)=phi(sigma(x)+phi(x)) is started at these numbers then the sequence does not converge.

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

Offset

1,1

Comments

These terms are only conjectures.

These terms survive 1000 iterations. - Sean A. Irvine, May 05 2025

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, A077081, A077082, A077083, A077084.

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