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 A373378 #7 Jun 05 2024 19:23:13
%S A373378 0,1,1,2,1,1,1,3,2,1,1,4,1,1,2,4,1,1,1,6,2,1,1,1,2,1,3,8,1,1,1,5,2,1,
%T A373378 2,6,1,1,2,1,1,1,1,12,1,1,1,2,2,9,2,14,1,1,2,1,2,1,1,4,1,1,1,6,2,1,1,
%U A373378 18,2,1,1,1,1,1,5,20,2,1,1,8,4,1,1,2,2,1,2,1,1,3,2,24,2,1,2,1,1,1,1,10,1,1,1,1,1
%N A373378 a(n) = gcd(A003415(n), A059975(n)), where A003415 is the arithmetic derivative and A059975 is fully additive with a(p) = p-1.
%H A373378 Antti Karttunen, <a href="/A373378/b373378.txt">Table of n, a(n) for n = 1..16384</a>
%F A373378 For n >= 1, a(n) is a multiple of A373377(n).
%o A373378 (PARI)
%o A373378 A003415(n) = if(n<=1, 0, my(f=factor(n)); n*sum(i=1, #f~, f[i, 2]/f[i, 1]));
%o A373378 A059975(n) = {my(f = factor(n)); sum(i = 1, #f~, f[i, 2]*(f[i, 1] - 1)); };
%o A373378 A373378(n) = gcd(A003415(n), A059975(n));
%Y A373378 Cf. A003415, A059975.
%Y A373378 Cf. A368998 (positions of even terms), A368999 (of odd terms).
%Y A373378 Cf. also A373364, A373368, A373369, A373377.
%K A373378 nonn
%O A373378 1,4
%A A373378 _Antti Karttunen_, Jun 05 2024