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 A351539 #16 Feb 17 2022 00:02:24
%S A351539 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,0,0,0,0,
%T A351539 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,0,0,
%U A351539 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,0,0,0,0,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1
%N A351539 Number of odd prime factors p of n such that p^(1+valuation(n,p)) divides sigma(n).
%H A351539 Antti Karttunen, <a href="/A351539/b351539.txt">Table of n, a(n) for n = 1..65537</a>
%H A351539 <a href="/index/Si#SIGMAN">Index entries for sequences related to sigma(n)</a>
%F A351539 For all n >= 1, a(n) <= A351439(n) <= A001221(n).
%e A351539 For n = 2235 = 3 * 5 * 149, sigma(2235) = 3600 = 2^4 * 3^2 * 5^2, and thus for two of the three odd prime factors of 2235, a higher power of the same prime divides sigma(2235), and therefore a(2235) = 2. This is also the least n for which a(n) > 1.
%t A351539 {0}~Join~Table[Function[m, Count[DeleteCases[FactorInteger[n][[All, 1]], 2], _?(Mod[m, #^(1 + IntegerExponent[n, #])] == 0 &)]][DivisorSigma[1, n]], {n, 2, 120}] (* _Michael De Vlieger_, Feb 16 2022 *)
%o A351539 (PARI) A351539(n) = { my(f=factor(n),s=sigma(n)); sum(k=1,#f~,(f[k,1]%2)&&(0==(s%(f[k,1]^(1+f[k,2]))))); };
%Y A351539 Cf. A000203, A001221, A286561, A351439, A351540 (positions of nonzero terms).
%K A351539 nonn
%O A351539 1,2235
%A A351539 _Antti Karttunen_, Feb 16 2022