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 A343220 #11 May 23 2021 03:20:32
%S A343220 0,0,1,0,0,2,1,0,0,1,1,2,0,2,2,0,1,0,1,1,3,2,1,2,0,1,1,2,1,5,1,1,3,2,
%T A343220 2,0,0,2,2,1,0,6,1,2,1,2,1,2,0,0,3,1,1,2,2,2,3,2,1,5,0,2,2,0,1,6,1,2,
%U A343220 3,5,1,1,0,1,2,2,3,5,1,1,0,1,1,6,2,2,3,2,1,3,2,2,3,2,2,3,0,1,2,0,0,6,1,1,6
%N A343220 Number of unitary divisors d of n for which A003415(sigma(d)) > d.
%C A343220 Number of divisors d of n such that gcd(d,n/d) = 1 and d is in A343218.
%C A343220 Number of terms k of A343218 that divide n, and k and n/k are relatively prime.
%H A343220 Antti Karttunen, <a href="/A343220/b343220.txt">Table of n, a(n) for n = 1..65537</a>
%F A343220 a(n) = Sum_{d|n, gcd(d,n/d)=1} A343219(d).
%o A343220 (PARI)
%o A343220 A003415(n) = if(n<=1, 0, my(f=factor(n)); n*sum(i=1, #f~, f[i, 2]/f[i, 1]));
%o A343220 A343219(n) = (A003415(sigma(n))>n);
%o A343220 A343220(n) = sumdiv(n,d,if(1==gcd(d,n/d),A343219(d),0));
%Y A343220 Cf. A000203, A003415, A342925, A343218, A343219, A343225 (positions of 1's).
%K A343220 nonn,look
%O A343220 1,6
%A A343220 _Antti Karttunen_, Apr 09 2021