A361968 - OEIS

A361968

Unitary highly totient numbers: numbers k that have more solutions x to the equation uphi(x) = k than any smaller k, where uphi is the unitary totient function (A047994).

1, 6, 8, 12, 24, 48, 96, 120, 144, 240, 480, 576, 720, 1440, 2880, 4320, 5760, 8640, 10080, 17280, 20160, 30240, 34560, 40320, 60480, 80640, 120960, 241920, 362880, 483840, 725760, 967680, 1209600, 1451520, 2177280, 2419200, 2903040, 3628800, 4354560, 4838400

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OFFSET

1,2

COMMENTS

Indices of records of A361967.

The corresponding numbers of solutions are 2, 3, 4, 5, 8, 11, ... (A361971).

LINKS

Amiram Eldar, Table of n, a(n) for n = 1..51

MATHEMATICA

solnum[n_] := Length[invUPhi[n]]; seq[kmax_] := Module[{s = {}, solmax=0}, Do[sol = solnum[k]; If[sol > solmax, solmax = sol; AppendTo[s, k]], {k, 1, kmax}]; s]; seq[10^5] (* using the function invUPhi from A361966 *)

CROSSREFS

The unitary version of A097942.

Cf. A047994, A135347, A347771, A361966, A361967, A361969, A361970, A361971.

Sequence in context: A315873 A072057 A212351 * A327240 A274001 A324212

Adjacent sequences: A361965 A361966 A361967 * A361969 A361970 A361971

KEYWORD

nonn

AUTHOR

Amiram Eldar, Apr 01 2023

STATUS

approved