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 A046719 #20 Apr 22 2016 10:18:10
%S A046719 4,42,429,4244,41815,413436,4102567,40775008,405774711,4042049770,
%T A046719 40293025322,401878286460,4009949122673,40024266995482,
%U A046719 399594430078005,3990300329780096,39853419882545236,398095148341559286,3977036546783471193
%N A046719 Total number of digits in all primes with n digits.
%e A046719 There are 21 2-digit primes, so a(2)=2*21=42.
%t A046719 Flatten[Table[n*Differences[PrimePi[{10^(n - 1), 10^n}]], {n, 13}]] (* _Jayanta Basu_, Jun 27 2013 *)
%t A046719 With[{nn=14},Differences[PrimePi[10^Range[0,nn]]]*Range[nn]] (* This program generates only the first 14 terms of the sequence; Mathematica's PrimePi function cannot generate the 15th or higher terms *) (* _Harvey P. Dale_, Apr 22 2016 *)
%Y A046719 a(n)=n*b(n) where b(n) is A006879.
%K A046719 nonn,base
%O A046719 1,1
%A A046719 _Enoch Haga_
%E A046719 Corrected by _Jud McCranie_ and _N. J. A. Sloane_.