%I #16 May 20 2022 03:26:48

%S 0,0,0,1,0,2,0,2,1,2,0,6,0,2,2,3,0,6,0,6,2,2,0,10,1,2,2,6,0,12,0,4,2,

%T 2,2,14,0,2,2,10,0,12,0,6,6,2,0,14,1,6,2,6,0,10,2,10,2,2,0,26,0,2,6,5,

%U 2,12,0,6,2,12,0,22,0,2,6,6,2,12,0,14,3,2,0,26,2,2,2,10,0,26,2,6,2,2,2

%N a(n) = Sum_{d|n} omega(d)*omega(n/d).

%H Antti Karttunen, <a href="/A070288/b070288.txt">Table of n, a(n) for n = 1..10000</a>

%F a(n) = Sum_{prime p|n} A062799(n/p) = Sum_{prime p|n} Sum_{prime q|(n/p)} A000005(n/p/q). - _Max Alekseyev_, Aug 11 2016

%t a[n_] := DivisorSum[n, PrimeNu[#] * PrimeNu[n/#] &]; Array[a, 100] (* _Amiram Eldar_, May 20 2022 *)

%o (PARI) for(n=1,100,print1(sumdiv(n,d,omega(n/d)*omega(d)),","))

%Y Cf. A000005, A001221, A062799.

%K easy,nonn

%O 1,6

%A _Benoit Cloitre_, May 12 2002