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 A332042 #14 Dec 25 2024 06:01:57
%S A332042 1,0,1,1,0,2,0,1,0,0,0,4,0,1,0,0,0,2,0,1,0,0,0,5,0,0,0,0,0,2,0,2,0,0,
%T A332042 0,4,0,1,0,0,0,2,0,1,0,0,0,6,0,0,0,0,0,2,0,2,0,0,0,2,0,1,0,0,0,0,0,1,
%U A332042 0,0,0,9,0,1,0,0,0,0,0,2,0,0,0,3,0,0,0
%N A332042 Number of integers whose Dedekind psi function (A001615) values are n.
%H A332042 Amiram Eldar, <a href="/A332042/b332042.txt">Table of n, a(n) for n = 1..10000</a>
%F A332042 Asymptotic mean: Limit_{m->oo} (1/m) * Sum_{k=1..m} a(k) = Product_{p prime} (1 - 1/(p*(p+1))) = 0.7044422... (A065463). - _Amiram Eldar_, Dec 25 2024
%e A332042 a(6) = 2 since there are 2 solutions to psi(x) = 6: 4 and 5.
%t A332042 psi[1] = 1; psi[n_] := n * Times @@ (1 + 1/Transpose[FactorInteger[n]][[1]]); m = 100; v = Table[0, {m}]; Do[i = psi[k]; If[i <= m, v[[i]]++], {k, 1, m}]; v
%Y A332042 Cf. A001615, A054973, A063974, A065463, A332036, A332038, A332040.
%K A332042 nonn
%O A332042 1,6
%A A332042 _Amiram Eldar_, Feb 05 2020