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 A228415 #23 Mar 19 2024 12:29:10
%S A228415 1,7,54,534,4909,45405,385008,3539880,32260781,294001190,2564080248,
%T A228415 23271246324,211753431947
%N A228415 Count of the first 10^n primes which do not contain the digit 3.
%F A228415 a(n) <= 9^n. - _Charles R Greathouse IV_, May 21 2014
%e A228415 a(1) = 7 since there are 7 primes in the first 10 (through 29) that do not contain a 3. Namely: 2, 5, 7, 11, 17, 19, 29.
%t A228415 Table[Length[Select[Range[10^n], DigitCount[Prime[#], 10, 3] == 0 &]], {n, 0, 5}] (* _Robert Price_, Mar 23 2020 *)
%Y A228415 Cf. A231412, A228413-A228421, A097952, A091634-A091643.
%K A228415 more,nonn,base,hard
%O A228415 0,2
%A A228415 _Robert Price_, Nov 09 2013
%E A228415 a(12) from _Lucas A. Brown_, Mar 19 2024