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 A129406 #18 Sep 02 2024 01:28:47
%S A129406 2,1,2,2,1,2,1,1,0,0,2,0,1,1,1,1,1,0,1,0,2,2,0,2,2,0,2,0,0,0,2,1,0,2,
%T A129406 2,1,1,0,0,1,1,1,0,2,1,1,1,0,0,2,2,0,0,0,0,2,0,2,2,0,0,0,0,2,2,0,0,1,
%U A129406 0,2,1,1,2,2,2,0,0,2,2,1,0,2,0,1,2,2,2,1,2,1,1,1,1,0,2,2,0,2,1,1
%N A129406 Expansion of L(3, chi3) in base 3, where L(s, chi3) is the Dirichlet L-function for the non-principal character modulo 3.
%C A129406 Contributed to OEIS on Apr 15 2007 -- the 300th anniversary of the birth of Leonhard Euler.
%D A129406 Leonhard Euler, "Introductio in Analysin Infinitorum", First Part, Articles 176 and 292
%F A129406 chi3(k) = Kronecker(-3, k); chi3(k) is 0, 1, -1 when k reduced modulo 3 is 0, 1, 2, respectively; chi3 is A049347 shifted.
%F A129406 Series: L(3, chi3) = sum_{k >= 1} chi3(k) k^{-3} = 1 - 1/2^3 + 1/4^3 - 1/5^3 + 1/7^3 - 1/8^3 + 1/10^3 - 1/11^3 + ...
%F A129406 Closed form: L(3, chi3) = 4 Pi^3/(81 sqrt(3)).
%e A129406 L(3, chi3) = 0.8840238117500798567430579168710118077... = (0.2122121100201111101022022020002102211...)_3
%t A129406 nmax = 1000; First[ RealDigits[4 Pi^3/(81 Sqrt[3]) - (1/2) * 3^(-nmax), 3, nmax] ]
%Y A129406 Cf. A129404, A129405, A129407, A129408, A129409, A129410, A129411.
%Y A129406 Cf. A129658, A129659, A129660, A129661, A129662, A129663, A129664, A129665.
%K A129406 nonn,base,cons,easy
%O A129406 0,1
%A A129406 _Stuart Clary_, Apr 15 2007
%E A129406 Offset corrected by _R. J. Mathar_, Feb 05 2009