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 A091705 #14 Jul 21 2015 06:07:34
%S A091705 0,3,32,326,3231,31953,310456,3000349,28922364,278508004,2680391313,
%T A091705 25793058269,248228108241,2389543008906
%N A091705 Number of primes less than 10^n having at least one digit 4.
%e A091705 a(2) = 3 because of the 25 primes less than 10^2, 3 have at least one digit 4.
%t A091705 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], 4] != {}, c++ ]]; Print[c]; p--, {n, 1, 8}] (* _Robert G. Wilson v_, Feb 02 2004 *)
%Y A091705 a(n) + A091638(n) = A006880(n).
%Y A091705 Cf. A091644, A091645, A091646, A091647, A091706, A091707, A091708, A091709, A091710.
%K A091705 nonn,base
%O A091705 1,2
%A A091705 _Enoch Haga_, Jan 30 2004
%E A091705 Edited and extended by _Robert G. Wilson v_, Feb 02 2004
%E A091705 3 more terms from _Ryan Propper_, Aug 21 2005
%E A091705 a(13) from _Robert Price_, Nov 11 2013
%E A091705 a(14) from _Giovanni Resta_, Jul 21 2015