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a(n) = the sum of the prime factors of Sum_{i=1..n} prime(i).
1

%I #8 Mar 09 2020 09:11:11

%S 2,5,7,17,9,41,31,18,7,46,7,197,26,281,43,130,18,170,73,74,91,120,44,

%T 110,60,46,81,460,44,62,50,620,80,712,571,812,38,108,80,10,96,386,126,

%U 1280,74,1412,326,138,62,67,114,26,71,2030,3171,71,239,230,3711,7699

%N a(n) = the sum of the prime factors of Sum_{i=1..n} prime(i).

%H Amiram Eldar, <a href="/A075881/b075881.txt">Table of n, a(n) for n = 1..10000</a>

%F a(n) = A008472(A007504(n)). - _Amiram Eldar_, Mar 09 2020

%e The sum of the first three primes = 10 = 2 * 5, the prime factors of which sum to 7. Hence a(3) = 7.

%t Table[Apply[Plus, Transpose[FactorInteger[Sum[Prime[k], {k, 1, i}]]][[1]]], {i, 1, 100}]

%Y Cf. A007504, A008472.

%K nonn

%O 1,1

%A _Joseph L. Pe_, Oct 16 2002

%E Offset corrected by _Amiram Eldar_, Mar 09 2020