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 A229661 #10 Dec 11 2021 04:36:33
%S A229661 0,40,25,17,12,10,8,7,6,5,5,4,4,3,3,3,3,3,2,2,2,2,2,2,2,2
%N A229661 Rounded percentage of primes less than 10^n.
%C A229661 Please refer to the explanations and comments given in A006879 and A006880.
%F A229661 a(n) = pi(10^n)/10^(n-2) rounded.
%e A229661 There are 4 primes less than 10 (i.e., 2, 3, 5, 7), so a(1) = 40.
%t A229661 a[n_] := PrimePi[10^n]/10^(n-2) // Round;
%t A229661 (* or *) a[n_] := A006880[[n+1]]/10^(n-2) // Round; Table[Print["10^", n, " ", a[n], "%"]; a[n], {n, 0, 25}] (* _Jean-François Alcover_, Sep 27 2013 *)
%Y A229661 Cf. A000720, A006879, A006880, A007053, A040014, A006988.
%K A229661 nonn,base,hard,less
%O A229661 0,2
%A A229661 _Jean-François Alcover_, Sep 27 2013