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 A231411 #23 Jun 16 2019 13:21:06
%S A231411 0,0,15,232,2725,30350,324133,3386986,34984325,358604948,3657365837,
%T A231411 37164550469,376613845818,3808514755978
%N A231411 Total number of zero digits in primes less than 10^n.
%e A231411 a(3)=15, since there are 15 zeros in primes less than 1000. Namely: 101, 103, 107, 109, 307, 401, 409, 503, 509, 601, 607, 701, 709, 809, 907.
%t A231411 Table[Count[IntegerDigits[Prime[Range[PrimePi[10^n-1]]]], 0, 2], {n, 7}] (* _Robert Price_, Jun 16 2019 *)
%Y A231411 Cf. A231590-A231598, A119290, A119291-A119300.
%Y A231411 Cf. A033713.
%K A231411 nonn,base,more
%O A231411 1,3
%A A231411 _Robert Price_, Nov 08 2013
%E A231411 a(14) from _Giovanni Resta_, Jul 20 2015