A348174 Indices k of records of low value in the ratios A348173(k)/k.

1, 2, 546, 2730, 13650, 51870, 101010, 199290, 505050, 881790, 996450, 1919190, 32626230, 140100870, 654443790, 865554690

Offset

1,2

Comments

The maximal possible value of the ratio A348173(k)/k is 1 which occurs at the terms of A348004.

The rounded values of the corresponding records are 1, 0.5, 0.478, 0.469, 0.466, 0.465, 0.4642, 0.4638, 0.4621, 0.4620, 0.460, 0.453, 0.450, 0.447, 0.446, 0.445, ...

a(17) > 1.4*10^9.

Links

Table of n, a(n) for n=1..16.

Mathematica

f[p_, e_] := p^e - 1; uphi[1] = 1; uphi[n_] := Times @@ f @@@ FactorInteger[n]; r[n_] := Plus @@ DeleteDuplicates[uphi /@ Select[Divisors[n], CoprimeQ[#, n/#] &]]/n; rm = 2; seq = {}; Do[r1 = r[n]; If[r1 < rm, rm = r1; AppendTo[seq, n]], {n, 1, 2*10^5}]; seq

Crossrefs

The unitary version of A348159.

Cf. A348003, A348004, A348173.

Sequence in context: A101702 A119780 A120840 * A348003 A058429 A336784

Adjacent sequences: A348171 A348172 A348173 * A348175 A348176 A348177

Keyword

nonn,more

Author

Amiram Eldar, Oct 04 2021

Status

approved