A102862 - OEIS

A102862

Numbers of prime factors of the sum of the first n primes.

1, 1, 2, 1, 3, 1, 2, 2, 4, 2, 6, 1, 3, 1, 4, 2, 5, 2, 4, 3, 4, 2, 3, 3, 4, 4, 5, 2, 5, 4, 5, 2, 4, 2, 3, 2, 5, 2, 3, 5, 3, 3, 3, 2, 4, 2, 3, 2, 5, 3, 4, 6, 4, 2, 2, 3, 4, 2, 2, 1, 3, 3, 3, 1, 2, 2, 3, 3, 3, 3, 5, 2, 3, 4, 2, 3, 4, 3, 6, 4, 3, 2, 6, 4, 5, 3, 5, 4, 4, 3, 5, 2, 2, 2, 6, 1, 4, 3, 5, 1, 5, 1, 7, 2, 5

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OFFSET

1,3

LINKS

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

FORMULA

a(n) = A001222(A007504(n)). - Amiram Eldar, Mar 09 2020

EXAMPLE

a(3) = 2 because 2+3+5 = 10 = 2*5.

a(5) = 3 because 2+3+5+7+11 = 28 = 2*2*7.

MATHEMATICA

PrimeOmega @ Accumulate @ Select[Range[230], PrimeQ] (* Amiram Eldar, Mar 09 2020 *)