

A328858


Numbers with a record number of distinct values of the Euler totient function applied to their divisors (A319696).


4



1, 3, 8, 15, 32, 45, 72, 105, 144, 216, 288, 432, 792, 864, 1296, 1584, 1728, 2376, 2592, 3168, 4752, 9504, 14256, 19008, 28512, 38016, 54000, 57024, 85536, 108000, 114048, 162000, 171072, 216000, 218592, 228096, 324000, 342144, 437184, 465696, 648000, 655776
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OFFSET

1,2


COMMENTS

The corresponding record values are 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 13, 14, 16, 17, 18, 19, 20, 21, 22, 26, 32, 34, 38, 42, 44, 45, 50, 52, 54, 58, 59, 62, 63, 64, 66, 71, 72, 76, 78, 83, 84, ...


LINKS

Amiram Eldar, Table of n, a(n) for n = 1..100


EXAMPLE

The first 10 terms of A319696(k) are 1, 1, 2, 2, 2, 2, 2, 3, 3, 2. The record values 1, 2, and 3 are obtained at k = 1, 3, and 8. Therefore this sequence begins with 1, 3, 8.


MATHEMATICA

f[n_] := Length @ Union[EulerPhi /@ Divisors[n]]; fm = 0; s = {}; Do[f1 = f[n]; If[f1 > fm, fm = f1; AppendTo[s, n]], {n, 1, 660000}]; s


CROSSREFS

Cf. A000010, A102190, A319696.
Sequence in context: A196087 A295735 A309052 * A277224 A090741 A255835
Adjacent sequences: A328855 A328856 A328857 * A328859 A328860 A328861


KEYWORD

nonn


AUTHOR

Amiram Eldar, Oct 28 2019


STATUS

approved



