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 A348215 #10 Oct 09 2021 04:11:43 %S A348215 0,1,0,3,0,3,0,7,0,5,0,7,0,7,0,15,0,9,0,15,0,11,0,15,0,13,0,21,0,15,0, %T A348215 31,0,17,0,25,0,19,0,31,0,21,0,33,0,23,0,31,0,25,0,39,0,27,0,49,0,29, %U A348215 0,31,0,31,57,120,0,33,0,51,0,35,0,57,0,37,0,57 %N A348215 a(n) is the sum of the iterated A348158 starting from n until a fixed point is reached. %C A348215 The first odd number k with a(k) > 0 is k = 63. %H A348215 Amiram Eldar, <a href="/A348215/b348215.txt">Table of n, a(n) for n = 1..10000</a> %F A348215 a(n) = 0 if and only if n is in A326835. %F A348215 a(2*n) > 0 for all n. %e A348215 a(4) = 3 since the iterations of the map x -> A348158(x) starting from 4 are 4 -> 3. %e A348215 a(64) = 120 since the iterations of the map x -> A348158(x) starting from 64 are 64 -> 63 -> 57, and 63 + 57 = 120. %t A348215 f[n_] := Plus @@ DeleteDuplicates @ Map[EulerPhi, Divisors[n]]; a[n_] := Plus @@ Most @ FixedPointList[f, n] - n; Array[a, 100] %Y A348215 Cf. A092693, A326835, A348158, A348213, A348214. %K A348215 nonn %O A348215 1,4 %A A348215 _Amiram Eldar_, Oct 07 2021