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a(n) = Sum_{k=1..n} (bigomega(k)-omega(k)).
2

%I #18 Sep 17 2024 04:03:59

%S 0,0,0,1,1,1,1,3,4,4,4,5,5,5,5,8,8,9,9,10,10,10,10,12,13,13,15,16,16,

%T 16,16,20,20,20,20,22,22,22,22,24,24,24,24,25,26,26,26,29,30,31,31,32,

%U 32,34,34,36,36,36,36,37,37,37,38,43,43,43,43,44,44,44,44,47,47,47,48

%N a(n) = Sum_{k=1..n} (bigomega(k)-omega(k)).

%H Vaclav Kotesovec, <a href="/A069812/b069812.txt">Table of n, a(n) for n = 1..10000</a>

%F a(n) ~ A136141 * n, where A136141 = 0.773156669... - _Vaclav Kotesovec_, Sep 01 2019

%F G.f.: (1/(1 - x)) * Sum_{p prime, k>=2} x^(p^k)/(1 - x^(p^k)). - _Ilya Gutkovskiy_, Sep 03 2019

%t Accumulate[Table[PrimeOmega[n]-PrimeNu[n],{n,80}]] (* _Harvey P. Dale_, Oct 10 2015 *)

%o (PARI) lista(nmax) = {my(s = 0, e); for(n = 1, nmax, e = factor(n)[, 2]; s += vecsum(e) - #e; print1(s, ", "));} \\ _Amiram Eldar_, Sep 17 2024

%Y Cf. A001221, A001222, A046660, A136141.

%K easy,nonn

%O 1,8

%A _Benoit Cloitre_, Apr 30 2002