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 A188834 #17 Apr 16 2018 03:12:39 %S A188834 3,3,2,3,3,7,5,8,9,9,2,6,7,1,8,8,2,4,2,5,9,1,6,3,7,8,4,5,4,9,9,9,0,1, %T A188834 4,9,9,9,2,8,8,3,7,2,7,0,0,5,0,1,3,6,4,1,6,3,7,9,4,2,2,3,3,6,0,5,1,2, %U A188834 1,8,0,5,9,6,5,2,7,6,7,4,5,5,8,1,6,7,3,8,3,5,2,8,2,2,9,2,2,3,3,4,3 %N A188834 Decimal expansion of limit sqrt(2*sqrt(4*sqrt(6*sqrt(8*sqrt(10*...sqrt(2*n...)))))). %H A188834 G. C. Greubel, <a href="/A188834/b188834.txt">Table of n, a(n) for n = 1..10000</a> %e A188834 3.3233758992671882... %p A188834 with(numtheory); %p A188834 P:=proc(i) %p A188834 local a,n; %p A188834 a:=1; %p A188834 for n from i by -1 to 1 do a:=2*n*sqrt(a); od; %p A188834 print(evalf(sqrt(a),1000)); %p A188834 end: %p A188834 P(5000); %t A188834 digits = 101; p[m_] := p[m] = Fold[N[Sqrt[#2*#1], digits] &, 1, Range[2*m, 2, -2]] // RealDigits[#, 10, digits]& // First; p[digits]; p[m = 2*digits]; While[p[m] != p[m/2], m = 2*m]; p[m] (* _Jean-François Alcover_, Feb 24 2014 *) %Y A188834 Cf. A112302, A171759, A188835. %K A188834 nonn,cons %O A188834 1,1 %A A188834 _Paolo P. Lava_, Apr 12 2011