A353785 - OEIS

%I #7 May 08 2022 19:50:45

%S 1,1,2,1,1,2,4,1,1,1,2,2,1,4,2,1,3,1,2,1,4,2,4,2,1,1,4,4,1,2,16,3,2,3,

%T 4,1,1,2,2,1,1,4,2,2,1,4,8,2,1,1,6,1,9,4,2,4,2,1,2,2,1,16,4,1,1,2,2,3,

%U 4,4,12,1,1,1,2,2,4,2,8,1,11,1,2,4,3,2,2,2,3,1,4,4,16,8,2,6,7,1,2,1,1,6,4,1,4

%N a(n) = A353783(n) / A080398(n).

%H Michael De Vlieger, <a href="/A353785/b353785.txt">Table of n, a(n) for n = 1..10000</a>

%H <a href="/index/Si#SIGMAN">Index entries for sequences related to sigma(n)</a>

%F a(n) = A353783(n) / A080398(n).

%t Array[Apply[LCM, DivisorSigma[1, Power @@@ FactorInteger[#]]]/Apply[Times, FactorInteger[DivisorSigma[1, #]][[All, 1]]] &, 105] (* _Michael De Vlieger_, May 08 2022 *)

%o (PARI)

%o A080398(n) = factorback(factor(sigma(n))[, 1]);

%o A353783(n) = { my(f=factor(n)~); lcm(vector(#f, i, sigma(f[1, i]^f[2, i]))); };

%o A353785(n) = (A353783(n) / A080398(n));

%Y Cf. A000203, A080398, A353783.

%K nonn

%O 1,3

%A _Antti Karttunen_, May 08 2022