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 A173296 #10 Feb 25 2019 08:22:04
%S A173296 1,-4,28,-96,1328,-4672,33472,-121856,3597056,-13417472,33655808,
%T A173296 -127508480,5829259264,-22308732928,171393728512,-660468137984,
%U A173296 40831182635008,-22589996269568,175323994652672,-681560447647744
%N A173296 Numerators of the inverse binomial transform of the Leibniz series for Pi/4.
%C A173296 The series terms for Pi/4 are 1, -1/3, 1/5, -1/7, 1/9, -1/11, + ...
%C A173296 Its inverse binomial transform is 1, -4/3, 28/15, -96/35, 1328/315, -4672/693, + ...
%H A173296 Wikipedia, <a href="http://en.wikipedia.org/wiki/Leibniz_series">Leibniz series</a>
%p A173296 L := [seq((-1)^n/(2*n+1),n=0..20)] ;
%p A173296 read("transforms") ; BINOMIALi(L) ;
%p A173296 apply(numer,%) ; # _R. J. Mathar_, Jul 06 2011
%Y A173296 Cf. A077595, A173294, A001803.
%K A173296 frac,sign
%O A173296 0,2
%A A173296 _Paul Curtz_, Feb 15 2010
%E A173296 a(3) replaced with reduced numerator and a(5) onwards added by _R. J. Mathar_, Jul 06 2011