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A229121 a(n) = Omega(n)^2 - omega(n)^2. 1

%I #29 Sep 16 2023 05:27:08

%S 0,0,0,3,0,0,0,8,3,0,0,5,0,0,0,15,0,5,0,5,0,0,0,12,3,0,8,5,0,0,0,24,0,

%T 0,0,12,0,0,0,12,0,0,0,5,5,0,0,21,3,5,0,5,0,12,0,12,0,0,0,7,0,0,5,35,

%U 0,0,0,5,0,0,0,21,0,0,5,5,0,0,0,21,15,0,0

%N a(n) = Omega(n)^2 - omega(n)^2.

%C If n is squarefree, a(n) = 0. If n is a semiprime, then a(n) = 3 - 3 * mu(n).

%H T. D. Noe, <a href="/A229121/b229121.txt">Table of n, a(n) for n = 1..10000</a>

%F a(n) = A001222(n)^2 - A001221(n)^2.

%F a(n) = A046660(n) * A080256(n). - _Amiram Eldar_, Sep 16 2023

%p with(numtheory); A001221 := proc(n) nops(numtheory[factorset](n)) end: seq(bigomega(k)^2 - A001221(k)^2, k=1..100);

%t Table[PrimeOmega[n]^2 - PrimeNu[n]^2, {n, 100}] (* _T. D. Noe_, Sep 17 2013 *)

%Y Cf. A001221 (omega), A001222 (Omega), A046660 (difference), A080256 (sum).

%K nonn,easy

%O 1,4

%A _Wesley Ivan Hurt_, Sep 17 2013

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Last modified May 3 08:32 EDT 2024. Contains 372207 sequences. (Running on oeis4.)