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 A378646 #8 Dec 03 2024 19:50:09
%S A378646 1,1,1,2,1,3,1,4,2,3,1,4,1,3,3,8,1,4,1,6,3,3,1,8,2,3,4,8,1,1,1,16,3,3,
%T A378646 3,10,1,3,3,10,1,1,1,8,8,3,1,16,2,8,3,8,1,12,3,12,3,3,1,10,1,3,8,32,3,
%U A378646 1,1,8,3,9,1,16,1,3,8,8,3,1,1,20,8,3,1,8,3,3,3,16,1,14,3,8,3,3,3,32,1,8,8,14,1,1,1,18,13
%N A378646 Dirichlet convolution of A000027 and A378643.
%C A378646 First negative value is a(140) = -2.
%C A378646 Odd bisection is not A352063: a(472*2 + 1) = 102 != A352063(472) = A074206(945) = 132. Note that 945 is the first odd abundant number, A005231.
%H A378646 Antti Karttunen, <a href="/A378646/b378646.txt">Table of n, a(n) for n = 1..20000</a>
%F A378646 a(n) = Sum_{d|n} d*A378643(n/d).
%F A378646 a(n) = A074206(n) if n is a non-abundant number (A263837), and apparently never when n is abundant, A005101.
%o A378646 (PARI) A378646(n) = sumdiv(n,d,d*A378643(n/d));
%Y A378646 Cf. A000027, A005101, A005231, A074206, A103977, A378643, A378645 (Dirichlet inverse).
%K A378646 sign
%O A378646 1,4
%A A378646 _Antti Karttunen_, Dec 03 2024