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 A231790 #9 May 21 2014 17:10:47
%S A231790 0,25,279,3363,39395,485191,5269618,56745409,607655311,6578438247,
%T A231790 68950399755
%N A231790 Count of the first 10^n primes containing at least one 4's digit.
%F A231790 a(n) ~ 10^n. - _Charles R Greathouse IV_, May 21 2014
%e A231790 a(2)=25 because there are 25 primes not greater than 541 (the 100th prime) that contain a 4's digit. Namely: 41, 43, 47, 149, 241, 347, 349, 401, 409, 419, 421, 431, 433, 439, 443, 449, 457, 461, 463, 467, 479, 487, 491, 499, 541.
%t A231790 cnt = 0; Table[Do[p = Prime[k]; If[MemberQ[IntegerDigits[p], 4], cnt++], {k, 10^(n - 1) + 1, 10^n}]; cnt, {n, 5}] (* _T. D. Noe_, Nov 13 2013 *)
%Y A231790 Cf. A231726-A231790, A231792-A231796, A091634-A091643, A231412, A228413-A228421.
%K A231790 more,nonn,base
%O A231790 1,2
%A A231790 _Robert Price_, Nov 13 2013