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 A378432 #8 Nov 26 2024 15:21:56
%S A378432 1,-2,-3,1,-5,8,-7,0,1,12,-11,-3,-13,16,17,0,-17,-4,-19,-5,23,24,-23,
%T A378432 2,1,28,-1,-7,-29,-44,-31,0,35,36,37,5,-37,40,41,2,-41,-60,-43,-11,-7,
%U A378432 48,-47,4,1,-8,53,-13,-53,0,57,2,59,60,-59,25,-61,64,-9,0,67,-92,-67,-17,71,-92,-71,6,-73,76,-9,-19,79
%N A378432 Dirichlet inverse of A296075, where A296075 is the sum of deficiencies of divisors of n.
%H A378432 Antti Karttunen, <a href="/A378432/b378432.txt">Table of n, a(n) for n = 1..20000</a>
%F A378432 a(1) = 1, and for n > 1, a(n) = -Sum_{d|n, d<n} A296075(n/d) * a(d).
%o A378432 (PARI)
%o A378432 A033879(n) = ((2*n)-sigma(n));
%o A378432 A296075(n) = sumdiv(n,d,A033879(d));
%o A378432 memoA378432 = Map();
%o A378432 A378432(n) = if(1==n,1,my(v); if(mapisdefined(memoA378432,n,&v), v, v = -sumdiv(n,d,if(d<n,A296075(n/d)*A378432(d),0)); mapput(memoA378432,n,v); (v)));
%Y A378432 Cf. A033879.
%Y A378432 Dirichlet inverse of A296075.
%Y A378432 Möbius transform of A323910.
%K A378432 sign
%O A378432 1,2
%A A378432 _Antti Karttunen_, Nov 26 2024