This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A348216 #11 Oct 09 2021 04:04:17 %S A348216 120,1320,2760,3480,3720,4920,5160,5640,6360,7080,7320,8040,8520,8760, %T A348216 9480,9960,10680,11640,12120,12360,12840,13080,13560,14520,15240, %U A348216 15720,16440,16680,17880,18120,18840,19560,20040,20760,21480,21720,22920,23160,23640,23880 %N A348216 Numbers k such that A348215(k) = k. %C A348216 Are there odd terms in this sequence? There are none below 10^8. %H A348216 Amiram Eldar, <a href="/A348216/b348216.txt">Table of n, a(n) for n = 1..10000</a> %e A348216 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. %t A348216 f[n_] := Plus @@ DeleteDuplicates @ Map[EulerPhi, Divisors[n]]; s[n_] := Plus @@ Most @ FixedPointList[f, n] - n; Select[Range[24000], s[#] == # &] %Y A348216 Cf. A082897, A348158, A348213, A348214, A348215. %K A348216 nonn %O A348216 1,1 %A A348216 _Amiram Eldar_, Oct 07 2021