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 A144540 #22 Feb 09 2018 09:09:17
%S A144540 6,1,4,2,1,0,4,5,4,1,2,4,4,1,7,1,3,9,4,8,5,8,4,8,5,3,1,9,5,3,6,9,3,2,
%T A144540 5,7,1,9,7,7,7,8,2,3,3,9,4,2,1,0,4,8,5,7,9,6,7,9,5,6,2,5,3,5,7,6,7,5,
%U A144540 4,1,5,0,8,2,9,0,3,6,4,1,0,7,9,6,2,8,3,8,0,3,4,4,1,4,6,4,3,9,0,4,2,3,0,5,9
%N A144540 Unique sequence of digits a(0), a(1), a(2), .. such that for all k >= 2, the number A(k) := Sum_{n = 0..k-1 } a(n)*10^n satisfies 12^A(k) == A(k) mod 10^k.
%D A144540 M. Ripà, La strana coda della serie n^n^...^n, Trento, UNI Service, Nov 2011, p. 69-78. ISBN 978-88-6178-789-6.
%D A144540 Ilan Vardi, "Computational Recreations in Mathematica," Addison-Wesley Publishing Co., Redwood City, CA, 1991, pages 226-229.
%H A144540 Robert G. Wilson v, <a href="/A144540/b144540.txt">Table of n, a(n) for n = 0..1024</a>
%H A144540 J. Jimenez Urroz and J. Luis A. Yebra, <a href="http://www.cs.uwaterloo.ca/journals/JIS/VOL12/Yebra/yebra4.html">On the equation a^x == x (mod b^n)</a>, J. Int. Seq. 12 (2009) #09.8.8.
%e A144540 614210454124417139485848531953693257197778233942104857967956253576754150829036...
%t A144540 (* Import Mmca coding for "SuperPowerMod" and "LogStar" from text file in A133612 and then *) $RecursionLimit = 2^14; f[n_] := SuperPowerMod[12, n + 1, 10^n]; Reverse@ IntegerDigits@ f@ 105 (* _Robert G. Wilson v_, Mar 06 2014 *)
%Y A144540 Cf. A133612, A133613, A133614, A133615, A133616, A133617, A133618, A133619, A144539, A144541, A144542, A144543, A144544.
%K A144540 nonn,base
%O A144540 0,1
%A A144540 _N. J. A. Sloane_, Dec 20 2008
%E A144540 a(68) onward from _Robert G. Wilson v_, Mar 06 2014