login
Möbius transform of A062401, where A062401(n) = phi(sigma(n)).
2

%I #14 May 07 2022 09:42:57

%S 1,1,1,4,1,1,3,2,10,3,3,4,5,3,5,22,5,10,7,2,11,7,7,2,28,5,4,12,7,11,

%T 15,6,11,11,11,40,17,7,17,10,11,11,19,8,6,15,15,22,32,26,17,26,17,4,

%U 19,6,23,15,15,14,29,15,22,90,17,23,31,14,23,25,23,20,35,17,24,28,25,17,31,14,94,23,23,44,29,19

%N Möbius transform of A062401, where A062401(n) = phi(sigma(n)).

%C The first negative term is a(1944) = -76.

%H Antti Karttunen, <a href="/A353647/b353647.txt">Table of n, a(n) for n = 1..16384</a>

%F a(n) = Sum_{d|n} A008683(n/d) * A062401(d).

%t a[n_] := DivisorSum[n, MoebiusMu[n/#] * EulerPhi[DivisorSigma[1, #]] &]; Array[a, 100] (* _Amiram Eldar_, May 06 2022 *)

%o (PARI) A353647(n) = sumdiv(n,d,moebius(n/d)*eulerphi(sigma(d)));

%Y Cf. A000010, A000203, A008683, A062401.

%K sign

%O 1,4

%A _Antti Karttunen_, May 06 2022