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A073395 Product of sums of prime factors of n: with and without repetition. 2

%I #26 Dec 21 2021 23:30:36

%S 0,4,9,8,25,25,49,12,18,49,121,35,169,81,64,16,289,40,361,63,100,169,

%T 529,45,50,225,27,99,841,100,961,20,196,361,144,50,1369,441,256,77,

%U 1681,144,1849,195,88,625,2209,55,98,84,400,255,2809,55,256,117,484

%N Product of sums of prime factors of n: with and without repetition.

%H T. D. Noe, <a href="/A073395/b073395.txt">Table of n, a(n) for n = 1..10000</a>

%F a(n) = A008472(n)*A001414(n).

%F a(m) is a square for all squarefree numbers m.

%F a(p^k) = k*p^2 for primes p.

%e a(15) = (3+5)*(3+5) = 8*8 = 64 (n squarefree); a(16) = (2)*(2+2+2+2) = 2*8 = 16 (n prime-power); a(17) = (17)*(17) = 289 (n prime); a(18) = (2+3)*(2+3+3) = 5*8 = 40.

%t a[n_] := With[{fi = FactorInteger[n]}, Plus @@ fi[[All, 1]]*Plus @@ Apply[Times, fi, 1]]; a[1]=0; Table[a[n], {n, 1, 57}] (* _Jean-François Alcover_, Jul 19 2012 *)

%o (Haskell)

%o a073395 n = a008472 n * a001414 n

%o -- _Reinhard Zumkeller_, Oct 28 2015 (fixed), Mar 29 2012

%o (Python)

%o from sympy import primefactors, factorint

%o def a001414(n):

%o f=factorint(n)

%o return sum([i*f[i] for i in f])

%o def a(n): return 0 if n==1 else sum(primefactors(n))*a001414(n)

%o print([a(n) for n in range(1, 101)]) # _Indranil Ghosh_, Jun 23 2017

%Y Cf. A073396.

%Y Cf. A027746, A027748.

%Y Cf. A008472, A001414.

%K nonn,nice

%O 1,2

%A _Reinhard Zumkeller_, Jul 30 2002

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Last modified April 19 15:03 EDT 2024. Contains 371793 sequences. (Running on oeis4.)