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A074375 s(s+3)/2 where s is the sum of the prime factors of n (with repetition). 2

%I

%S 0,5,9,14,20,20,35,27,27,35,77,35,104,54,44,44,170,44,209,54,65,104,

%T 299,54,65,135,54,77,464,65,527,65,119,209,90,65,740,252,152,77,902,

%U 90,989,135,77,350,1175,77,119,90,230,170,1484,77,152,104,275,527,1829,90

%N s(s+3)/2 where s is the sum of the prime factors of n (with repetition).

%H Neville Holmes, <a href="http://www.comp.utas.edu.au/users/nholmes/sqncs/cmbntns.htm#A074375">Integer Sequence Combinations</a>

%e a(20) = 9(9+3)/2 = 54 because 9 = 2+2+5 and 20 = 2*2*5.

%t spf[n_]:=Module[{c=Total[Times@@@FactorInteger[n]]},(c(c+3))/2]; Join[ {0}, Rest[Array[spf,60]]] (* _Harvey P. Dale_, Aug 16 2011 *)

%Y Applies A000096 to A001414. Cf. A074373, A074374.

%K easy,nonn

%O 1,2

%A _W. Neville Holmes_, Aug 29 2002

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Last modified November 19 22:34 EST 2019. Contains 329323 sequences. (Running on oeis4.)