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 A138733 #4 Mar 31 2012 10:22:07
%S A138733 5,190,4531,99232,2125044,45190209,958768567,20325471335,430773893366,
%T A138733 9128872855695,193450867955197,4099389985205820,86869246502331992,
%U A138733 1840823999333339814,39008411877876819180,826616742911186406242
%N A138733 Second term of continued fraction for 2n-th Du Bois Reymond constant.
%F A138733 a(n) = floor(1/C(2n)), where C(2n) is the 2n-th Du Bois Reymond constant. [From _Max Alekseyev_, Sep 15 2009]
%t A138733 a = {}; Do[AppendTo[a,Last[ContinuedFraction[FullSimplify[TrigToExp[ -3 - 2Residue[x^2/((Tan[x] - x) (1 + x^2)^n), {x,I}]]], 2]]], {n, 1, 9}]; a (*Artur Jasinski*)
%Y A138733 Cf. A062545, A062546, A085466, A085467, A138729, A138730, A138731, A138732, A138733.
%K A138733 nonn
%O A138733 1,1
%A A138733 _Artur Jasinski_, Mar 26 2008
%E A138733 Extended by _Max Alekseyev_, Sep 15 2009