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 A378649 #6 Dec 04 2024 10:17:02
%S A378649 1,1,2,2,4,2,6,4,6,4,10,8,12,6,8,8,16,10,18,10,12,10,22,20,20,12,18,
%T A378649 12,28,20,30,16,20,16,24,32,36,18,24,26,40,24,42,20,24,22,46,48,42,20,
%U A378649 32,24,52,30,40,32,36,28,58,64,60,30,36,32,48,32,66,32,44,28,70,88,72,36,40,36,60,36,78,60,54,40,82
%N A378649 Möbius transform of A378647.
%H A378649 Antti Karttunen, <a href="/A378649/b378649.txt">Table of n, a(n) for n = 1..20000</a>
%F A378649 a(n) = Sum_{d|n} A008683(d)*A378647(n/d):
%F A378649 a(n) = (A378644(n)+A378647(n)) / 2.
%F A378649 a(n) = A000010(n) = phi(n) only when n is a non-abundant number (A263837), and apparently never when n is abundant, A005101.
%o A378649 (PARI) A378649(n) = sumdiv(n,d,moebius(d)*A378647(n/d));
%Y A378649 Cf. A000010, A005101, A008683, A067824, A103977, A263837, A378644, A378647 (inverse Möbius transform).
%K A378649 nonn
%O A378649 1,3
%A A378649 _Antti Karttunen_, Dec 03 2024