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 A013707 #37 Jul 27 2017 17:55:49
%S A013707 6,9,3,1,3,7,1,8,0,6,5,9,9,4,5,3,0,9,3,9,7,2,3,2,1,2,1,4,7,4,1,7,6,5,
%T A013707 6,8,0,4,8,3,0,0,1,3,4,4,3,9,6,1,5,2,5,3,7,6,6,8,8,8,0,1,1,7,3,0,2,1,
%U A013707 9,2,0,2,9,3,2,1,2,1,8,0,5,4,7,1,2,0,3,3,9,4,1,0,7,9,5,6,9,1,9,3,2,1,5,1,7
%N A013707 Decimal expansion of Sum_{k=1..50000} (-1)^(k+1) / k.
%H A013707 J. M. Borwein, P. B. Borwein and K. Dilcher, <a href="http://www.jstor.org/stable/2324715">Pi, Euler numbers and asymptotic expansions</a>, Amer. Math. Monthly, 96 (1989), 681-687.
%H A013707 J. M. Borwein, P. B. Borwein and K. Dilcher, <a href="/A013707/a013707.png">Pi, Euler numbers and asymptotic expansions</a>, Amer. Math. Monthly, 96 (1989), 681-687.
%H A013707 J. M. Borwein and R. M. Corless, <a href="http://www.cecm.sfu.ca/~jborwein/sloane/sloane.html">Review of "An Encyclopedia of Integer Sequences" by N. J. A. Sloane and Simon Plouffe</a>, SIAM Review, 38 (1996), 333-337.
%F A013707 log(2) + (Psi(25000 + 1/2) - Psi(25001))/2. - _Robert Israel_, Feb 03 2015
%t A013707 RealDigits[Sum[(-1)^(k+1)/k,{k,50000}],10,120][[1]] (* _Harvey P. Dale_, Jul 27 2017 *)
%Y A013707 Cf. A013705, A013706.
%K A013707 cons,nonn,easy,nice
%O A013707 0,1
%A A013707 _N. J. A. Sloane_
%E A013707 Corrected and extended by _Jon E. Schoenfield_, Feb 03 2015