A075881 a(n) = the sum of the prime factors of Sum_{i=1..n} prime(i).

2, 5, 7, 17, 9, 41, 31, 18, 7, 46, 7, 197, 26, 281, 43, 130, 18, 170, 73, 74, 91, 120, 44, 110, 60, 46, 81, 460, 44, 62, 50, 620, 80, 712, 571, 812, 38, 108, 80, 10, 96, 386, 126, 1280, 74, 1412, 326, 138, 62, 67, 114, 26, 71, 2030, 3171, 71, 239, 230, 3711, 7699

Offset

1,1

Links

Amiram Eldar, Table of n, a(n) for n = 1..10000

Formula

a(n) = A008472(A007504(n)). - Amiram Eldar, Mar 09 2020

Example

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

Mathematica

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

Crossrefs

Cf. A007504, A008472.

Sequence in context: A325210 A181447 A082088 * A208241 A089727 A113514

Adjacent sequences: A075878 A075879 A075880 * A075882 A075883 A075884

Keyword

nonn

Author

Joseph L. Pe, Oct 16 2002

Extensions

Offset corrected by Amiram Eldar, Mar 09 2020

Status

approved