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 A221648 #15 Nov 05 2014 16:24:23
%S A221648 0,-2,2,-7,24,-121,720,-5042,40324,-362893,3628841,-39916952,
%T A221648 479002203,-6227023411,87178303368,-1307674428809,20922790212198,
%U A221648 -355687429932747,6402373716747122,-121645100478614633,2432902008641837022,-51090942174965733088,1124000727801486784372
%N A221648 Floor(integral_{n=0..infinity} (log(x) - log(1 + x^2))^n/(1 + x^2)^2 dx).
%H A221648 Balarka Sen, <a href="/A221648/b221648.txt">Table of n, a(n) for n = 0..100</a>
%H A221648 G. Boros, V. H. Moll, <a href="http://dx.doi.org/10.1137/S0036144597317406">An Integral with three parameters</a>, SIAM Rev. 40 (1998), no. 4, 972-980.
%o A221648 (PARI) default(realprecision,100);for(n=0,50,print1(floor(intnum(x=0,oo,log(x/(1+x^2))^n/(1+x^2)^2))", "))
%K A221648 sign,easy
%O A221648 0,2
%A A221648 _Balarka Sen_, May 04 2013