A348216 Numbers k such that A348215(k) = k.

120, 1320, 2760, 3480, 3720, 4920, 5160, 5640, 6360, 7080, 7320, 8040, 8520, 8760, 9480, 9960, 10680, 11640, 12120, 12360, 12840, 13080, 13560, 14520, 15240, 15720, 16440, 16680, 17880, 18120, 18840, 19560, 20040, 20760, 21480, 21720, 22920, 23160, 23640, 23880

Offset: 1

Author

Amiram Eldar, Oct 07 2021

Keywords

• nonn

Comments

Are there odd terms in this sequence? There are none below 10^8.

Examples

			120 is a term since the iterations of the map x -> A348158(x) starting from 120 are 120 -> 63 -> 57 and A348215(120) = 57 + 63 = 120.
		

Links

• Amiram Eldar, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A082897, A348158, A348213, A348214, A348215.

Programs

Mathematica

f[n_] := Plus @@ DeleteDuplicates @ Map[EulerPhi, Divisors[n]]; s[n_] := Plus @@ Most @ FixedPointList[f, n] - n; Select[Range[24000], s[#] == # &]