The Riemann Prime Counting Function

I've been looking back over some of the entries in my Evernote notebook titled "Your Days Are Numbered" that used to be automatically posted to a blog that wanted to charge for the privilege of accessing my posts. However, the entries in the notebook remain and one that caught my attention related to the prime number 24121. OEIS A226473 states:

a(n) is the first prime index where the gap between R(n), Riemann's prime counting function, and Pi(n), the exact prime counting function, is greater than n.

The first terms in the sequence are:

109, 556, 1327, 3296, 5380, 10343, 11767, 19202, 19361, 19371, 24121, 42863 

The example given for 109 is that RiemannR(109) = 27.4664... and PrimePi(109) = 29 give the first gap greater than 1, hence a(1) = 109. 

24121 is the 11th member of the sequence. Pi(24121) = 2686 and RiemannR(24121) = 2674.9424 ... and 11 subtracted from 2686 is 2675. Thus the gap between PrimePi and RiemannR is more than 11 and so a(11) = 24121.

There is a discussion of the Riemann prime counting function on WolframAlpha.