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 A133833 #4 Nov 21 2018 19:21:03
%S A133833 11,97,101,997,10007,99991,1000003,9999991,10000000019,99999999977,
%T A133833 1000000000039,9999999999971,10000000000000061,99999999999999997,
%U A133833 1000000000000000003,9999999999999999961
%N A133833 Smallest and largest primes with number of decimal digits equal to n-th prime.
%e A133833 11, 97 are respectively the smallest and the largest 2-digit primes.
%e A133833 101, 997 are respectively the smallest and the largest 3-digit primes.
%e A133833 10007, 99991 are respectively the smallest and the largest 5-digit primes.
%t A133833 Table[{NextPrime[10^(n-1)],NextPrime[10^n,-1]},{n,Prime[Range[8]]}] // Flatten (* _Harvey P. Dale_, Nov 21 2018 *)
%Y A133833 Cf. A000040, A064490.
%K A133833 nonn,base
%O A133833 1,1
%A A133833 _Parthasarathy Nambi_, Jan 06 2008
%E A133833 More terms from _Harvey P. Dale_, Nov 21 2018