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 A300253 #11 Mar 14 2018 03:49:03 %S A300253 0,1,1,1,1,1,1,4,1,1,1,8,1,1,2,4,1,1,1,2,2,1,1,4,1,1,3,4,1,1,1,16,2,1, %T A300253 2,4,1,1,2,4,1,1,1,16,13,1,1,16,1,1,2,2,1,3,2,4,2,1,1,4,1,1,3,16,2,1, %U A300253 1,2,2,1,1,4,1,1,1,8,2,1,1,88,27,1,1,4,2,1,2,28,1,1,2,4,2,1,2,16,1,11,1,2,1,1,1,4,1 %N A300253 GCD of arithmetic derivative (A003415) and its Möbius transform (A300251). %H A300253 Antti Karttunen, <a href="/A300253/b300253.txt">Table of n, a(n) for n = 1..65537</a> %F A300253 a(n) = gcd(A003415(n), A300251(n)) = gcd(A003415(n), A300252(n)). %o A300253 (PARI) %o A300253 A003415(n) = {my(fac); if(n<1, 0, fac=factor(n); sum(i=1, matsize(fac)[1], n*fac[i, 2]/fac[i, 1]))}; \\ From A003415 %o A300253 A300251(n) = sumdiv(n,d,moebius(n/d)*A003415(d)); %o A300253 A300253(n) = gcd(A003415(n), A300251(n)); %Y A300253 Cf. A003415, A085731, A300245, A300251, A300252. %K A300253 nonn %O A300253 1,8 %A A300253 _Antti Karttunen_, Mar 08 2018