This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A309329 #16 Jul 27 2019 04:29:06
%S A309329 4,47,509,5273,53047,532887,5356259,53765483,539119753,5402600081,
%T A309329 54118210435,541947386821,5425907665571,54313871643797,
%U A309329 543611236251491,5440228524355329,54438462600610510,544705097744731559,5449909581264135103
%N A309329 Median of primes with n decimal digits.
%C A309329 The number of n-digit primes < a(n) equals the number of n-digit primes > a(n). The median of an even number of values is understood to be defined as the arithmetic mean of the two central elements.
%F A309329 a(n) = (prime(A006880(n-1) + ceiling(A006879(n)/2)) + prime(A006880(n-1) + floor(A006879(n)/2) + 1)) / 2.
%e A309329 a(1) = 4 because {2, 3, 5, 7} are the 4 one-digit primes. The 2 central elements of the sorted list are 3 and 5. 4 = (3 + 5)/2.
%e A309329 a(2) = 47 because it is the central element of the sorted list of the A006879(2) = 21 two-digit primes. There are 10 such primes < 47 and 10 such primes > 47.
%Y A309329 Cf. A006879, A006880, A309359
%K A309329 nonn,base,more
%O A309329 1,1
%A A309329 _Hugo Pfoertner_, Jul 25 2019