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 A353496 #7 Apr 27 2022 13:55:07 %S A353496 0,0,0,1,0,1,0,0,1,1,0,1,0,1,1,0,0,2,0,3,1,1,0,0,1,1,2,1,0,0,0,0,1,1, %T A353496 1,1,0,1,1,0,0,2,0,1,0,1,0,0,1,2,1,3,0,3,1,0,1,1,0,3,0,1,2,0,1,2,0,3, %U A353496 1,0,0,0,0,1,2,1,1,0,0,0,3,1,0,1,1,1,1,0,0,3,1,1,1,1,1,0,0,2,2,1,0,0,0,0,0 %N A353496 The arithmetic derivative of the largest proper divisor of n, reduced modulo 4, with a(1) = 0. %H A353496 Antti Karttunen, <a href="/A353496/b353496.txt">Table of n, a(n) for n = 1..65537</a> %F A353496 a(n) = A353493(A032742(n)) = A010873(A003415(A032742(n))). %o A353496 (PARI) %o A353496 A003415(n) = if(n<=1, 0, my(f=factor(n)); n*sum(i=1, #f~, f[i, 2]/f[i, 1])); %o A353496 A032742(n) = if(1==n,n,n/vecmin(factor(n)[,1])); %o A353496 A353496(n) = (A003415(A032742(n))%4); %Y A353496 Cf. A003415, A010873, A032742, A353493. %Y A353496 Cf. also A353490. %K A353496 nonn %O A353496 1,18 %A A353496 _Antti Karttunen_, Apr 26 2022