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 A378523 #7 Nov 30 2024 23:46:44
%S A378523 1,-3,-4,2,-6,14,-8,0,3,20,-12,-14,-14,26,27,0,-18,-17,-20,-18,35,38,
%T A378523 -24,4,5,44,0,-22,-30,-109,-32,0,51,56,53,34,-38,62,59,4,-42,-137,-44,
%U A378523 -30,-30,74,-48,0,7,-27,75,-34,-54,6,77,4,83,92,-60,146,-62,98,-36,0,89,-193,-68,-42,99,-199,-72,-28,-74,116
%N A378523 Dirichlet inverse of A332993, where A332993 is defined as a(1) = 1, and for n > 1, a(n) = n + a(A032742(n)), and A032742 is the largest proper divisor.
%H A378523 Antti Karttunen, <a href="/A378523/b378523.txt">Table of n, a(n) for n = 1..20000</a>
%F A378523 a(1) = 1, and for n > 1, a(n) = -Sum_{d|n, d<n} A332993(n/d) * a(d).
%o A378523 (PARI)
%o A378523 A332993(n) = if(1==n,n,n + A332993(n/vecmin(factor(n)[,1])));
%o A378523 memoA378523 = Map();
%o A378523 A378523(n) = if(1==n,1,my(v); if(mapisdefined(memoA378523,n,&v), v, v = -sumdiv(n,d,if(d<n,A332993(n/d)*A378523(d),0)); mapput(memoA378523,n,v); (v)));
%Y A378523 Cf. A032742, A332993.
%Y A378523 Cf. also A378524.
%K A378523 sign
%O A378523 1,2
%A A378523 _Antti Karttunen_, Nov 30 2024