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 A119929 #4 Jul 10 2011 18:41:28
%S A119929 2,7,5,5,5,0,8,4,0,9,9,8,7,6,6,9,4,4,0,0,2,5,2,9,1,9,6,9,5,1,5,5,9,1,
%T A119929 7,6,1,2,0,8,3,8,4,0,1,4,0,2,6,3,9,4,8,8,9,7,7,5,4,3,3,1,2,4,4,1,1,2,
%U A119929 3,1,4,2,4,5,5,5,3,5,1,7,0,2,9,2,5,6,7,1,4,2,9,3,0,8,4,3,0,4,1,3,1,4,6,2,8
%N A119929 Decimal expansion of the value of Minkowski's question mark function at Khinchin's constant (A002210).
%H A119929 <a href="/index/Me#MinkowskiQ">Index entries for sequences related to Minkowski's question mark function</a>
%e A119929 2.755508409987669440025291969515591761208384014026394889775...
%t A119929 (*ensure variables are appropriately Cleared*) Off[ContinuedFraction::incomp]; mq[x_] := (If[Element[x, Rationals], cf = ContinuedFraction[x], cf = ContinuedFraction[x, 80(*arbitrary precision*)]]; IntegerPart[x] + Sum[(-1)^(k)/2^(Sum[cf[[i]], {i, 2, k}] - 1), {k, 2, Length[cf]}]); RealDigits[mq[Khinchin],10]
%t A119929 RealDigits[(cf = ContinuedFraction[Khinchin, 80(*arbitrary precision*)]; IntegerPart[Khinchin] + Sum[(-1)^(k)/2^(Sum[cf[[i]], {i, 2, k}] - 1), {k,2, Length[cf]}]), 10]
%Y A119929 Cf. A119928.
%K A119929 cons,nonn
%O A119929 1,1
%A A119929 Joseph Biberstine (jrbibers(AT)indiana.edu), May 29 2006; corrected Jun 04 2006