A380546 - OEIS

%I #7 Jan 27 2025 09:59:18

%S 0,0,0,0,0,-1,0,0,0,0,0,-3,0,0,0,0,0,0,0,0,0,0,0,-2,0,0,0,-1,0,-5,0,0,

%T 0,0,0,0,0,0,0,-4,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,-7,0,0,0,-5,0,0,0,0,0,

%U 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,-3,0,0,0,0,0,-5,0,0,0,0,0,-8,0,0,0,0,0,0,0,0,0

%N Third coefficient of the lindep transform of A017666, denominator of sigma(n)/n.

%C See A339792 for a definition of lindep-transform.

%H Antti Karttunen, <a href="/A380546/b380546.txt">Table of n, a(n) for n = 1..65537</a>

%F a(n) = -(A017666(n)*A380544(n) + n*A380545(n)).

%o (PARI)

%o A017666(n) = (n/gcd(n, sigma(n)));

%o A380546(n) = { my(v=lindep([A017666(n), n, 1])); (v*sign(v[1]))[3]; };

%Y Cf. A017666, A380540, A380544, A380545.

%Y Cf. also A339792, A380464, A380543.

%K sign,new

%O 1,12

%A _Antti Karttunen_, Jan 27 2025