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 A096831 #10 Nov 16 2019 20:09:06 %S A096831 2,2,2,1,2,1,0,0,0,0,1,0,1,0,0,0,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,0,0,0, %T A096831 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,0,1, %U A096831 0,0,0,0,0,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0 %N A096831 Number of primes in the neighborhood with center = n-th primorial and radius = ceiling(log(n-th primorial)). %C A096831 What is exceptional in such neighborhoods of primorials is that in most cases no primes occur, i.e., these zones are peculiarly poor or empty of primes! %C A096831 Primes are scarce in these zones because log(A002110(n)) < prime(n), so A002110(n)+1 and A002110(n)-1 are the only numbers in the neighborhood that are not divisible by one of the first n primes. - _David Wasserman_, Nov 16 2007 %F A096831 a(n) = A096509(A002110(n)). %e A096831 n=7: 7th primorial=510510; radius=14, a(7)=0 because there are no primes in the relevant neighborhood. %e A096831 [1, 3], [4, 8], [26, 34], [2302, 2318] (around 2, 6, 30, 2310, respectively) are the only zones in which 2 primes were found. %Y A096831 Cf. A096509-A096523, A002110. %K A096831 nonn %O A096831 1,1 %A A096831 _Labos Elemer_, Jul 14 2004