[seqfan] Primes mod 6

[franktaw at netscape.net]

https://oeis.org/draft/A174695 is the number of primes, through the 
n-th prime, congruent to 5 (mod 6), minus the number congruent to 1 
(mod 6).

I seem to remember seeing something recently implying that this 
sequence is always nonnegative. I don't remember where, however. Can 
anyone clarify this, or am going into early senility?

Franklin T. Adams-Watters