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 A378597 #10 Dec 02 2024 17:43:18
%S A378597 0,0,1,0,3,-1,5,0,5,0,9,0,11,4,5,0,15,-5,17,-3,11,12,21,0,21,16,19,-9,
%T A378597 27,-8,29,0,23,24,25,0,35,28,29,0,39,-20,41,0,9,36,45,0,45,6,41,8,51,
%U A378597 -19,45,0,47,48,57,3,59,52,23,0,55,-44,65,24,59,-35,69,0,71,64,31,32,67,-56,77,0,65,72,81,9,75,76,77,-21
%N A378597 Möbius transform of A378450, where A378450 is the number of positive numbers k <= sigma(n) that are not a sum of any subset of distinct divisors of n.
%H A378597 Antti Karttunen, <a href="/A378597/b378597.txt">Table of n, a(n) for n = 1..20000</a>
%F A378597 a(n) = Sum_{d|n} A008683(d)*A378450(n/d).
%F A378597 a(n) = n - A378596(n).
%o A378597 (PARI)
%o A378597 A119347(n) = { my(c=[0]); fordiv(n,d, c = Set(concat(c,vector(#c,i,c[i]+d)))); (#c)-1; };
%o A378597 A378450(n) = (sigma(n)-A119347(n));
%o A378597 A378597(n) = sumdiv(n,d,moebius(n/d)*A378450(d));
%Y A378597 Cf. A008683, A119347, A378450, A378596.
%K A378597 sign,look
%O A378597 1,5
%A A378597 _Antti Karttunen_, Dec 02 2024