%I #18 Aug 21 2024 01:56:49
%S 0,0,3,6,10,15,15,28,21,21,28,66,28,91,45,36,36,153,36,190,45,55,91,
%T 276,45,55,120,45,66,435,55,496,55,105,190,78,55,703,231,136,66,861,
%U 78,946,120,66,325,1128,66,105,78,210,153,1431,66,136,91,253,496,1770,78
%N a(n) = sopfr(n)*(sopfr(n)+1)/2 where sopfr is the sum of the prime factors of n with repetition (A001414).
%H Neville Holmes, <a href="https://web.archive.org/web/20081204204102/http://www.comp.utas.edu.au/users/nholmes/sqncs/cmbntns.htm#A074374">Integer Sequence Combinations</a>
%F a(n) = A000217(A001414(n)).
%e a(10) = 7(7+1)/2 = 28 because 7 is the sum of the prime factors of 10.
%t f[n_]:=Module[{c=Total[Times@@@FactorInteger[n]]},(c(c+1))/2]; Join[{0,0}, Array[f,60,2]] (* _Harvey P. Dale_, Aug 21 2011 *)
%o (PARI) s(n)=sum(i=1,omega(n), component(component(factor(n),1),i)*component(component(factor(n),2),i))
%o a(n)=s(n)*(s(n)+1)/2
%Y Cf. A000217, A001414 (sopfr), A074372.
%K easy,nonn
%O 0,3
%A _W. Neville Holmes_, Aug 29 2002
%E More terms from _Benoit Cloitre_, Sep 02 2002