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 A324831 #7 Mar 16 2019 21:46:24 %S A324831 0,1,0,2,1,1,0,2,0,3,1,2,0,1,1,2,1,1,0,4,0,2,1,2,2,1,0,2,0,3,1,2,1,2, %T A324831 1,3,0,1,0,4,1,1,0,3,1,2,1,2,0,5,1,2,0,1,3,2,0,1,1,4,0,2,0,2,1,2,1,4, %U A324831 1,3,0,3,1,1,2,2,1,2,0,4,0,2,1,3,2,1,0,3,0,3,0,4,1,2,1,2,1,1,1,6,0,2,1,2,1 %N A324831 Number of divisors d of n such that A323243(d) == 1 (mod 3). %H A324831 Antti Karttunen, <a href="/A324831/b324831.txt">Table of n, a(n) for n = 1..10000</a> (based on Hans Havermann's factorization of A156552) %H A324831 <a href="/index/Bi#binary">Index entries for sequences related to binary expansion of n</a> %H A324831 <a href="/index/Pri#prime_indices">Index entries for sequences computed from indices in prime factorization</a> %H A324831 <a href="/index/Si#SIGMAN">Index entries for sequences related to sigma(n)</a> %F A324831 a(n) = A000005(n) - (A324830(n) + A324832(n)). %F A324831 For all n >= 1, a(A000040(n)) = A000035(n). %o A324831 (PARI) A324831(n) = sumdiv(n,d,(1==(A323243(d))%3)); %Y A324831 Cf. A000005, A000203, A156552, A323243, A324830, A324832. %K A324831 nonn %O A324831 1,4 %A A324831 _Antti Karttunen_, Mar 16 2019