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 A091647 #16 Jul 21 2015 06:06:35
%S A091647 1,9,66,561,4877,43685,399564,3694303,34433999,322852288,3041362298,
%T A091647 28758431735,272777483044,2594081699837
%N A091647 Number of primes less than 10^n having at least one digit 3.
%e A091647 a(2) = 9 because of the 25 primes less than 10^2, 9 have at least one digit 3.
%t A091647 NextPrim[n_] := Block[{k = n + 1}, While[ !PrimeQ[k], k++ ]; k]; c = 0; p = 1; Do[ While[ p = NextPrim[p]; p < 10^n, If[ Position[ IntegerDigits[p], 3] != {}, c++ ]]; Print[c]; p--, {n, 1, 8}] (* _Robert G. Wilson v_, Feb 02 2004 *)
%Y A091647 a(n) + A091637(n) = A006880(n).
%Y A091647 Cf. A091637, A091644, A091645, A091646, A091705, A091706, A091707, A091708, A091709, A091710.
%K A091647 nonn,base
%O A091647 1,2
%A A091647 _Enoch Haga_, Jan 30 2004
%E A091647 Edited and extended by _Robert G. Wilson v_, Feb 02 2004
%E A091647 3 more terms from _Ryan Propper_, Aug 20 2005
%E A091647 a(13) from _Robert Price_, Nov 11 2013
%E A091647 a(14) from _Giovanni Resta_, Jul 21 2015