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 A193240 #11 Sep 21 2017 04:01:22 %S A193240 110,11101,10110,11101011,1110100111000,1110001101111, %T A193240 1100100110101100,1110011000111111,1100110101111011100, %U A193240 1000110010101111,1111101001000000010 %N A193240 Trajectory of binary number 110 (decimal 6) under the operation "Reverse and Add" carried out with complex base -1+i. %H A193240 Kerry Mitchell, <a href="/A193240/b193240.txt">Table of n, a(n) for n = 0..500</a> %H A193240 W. J. Gilbert, <a href="https://www.maa.org/programs/faculty-and-departments/classroom-capsules-and-notes/arithmetic-in-complex-bases">Arithmetic in Complex Bases</a>, Mathematics Magazine, Vol. 57, No. 2 (Mar., 1984), pp. 77-81. %e A193240 The initial term is 110. Using complex base -1+i, this is -1-i. Reversing 110 gives 011, which is 0+i. Adding both terms gives -1+0i, which is 11101, the second term. %Y A193240 Cf A193239, number of steps needed to reach a palindrome with complex base -1+i. For that sequence, a(6)=-1, showing that decimal 6 (binary 110) seems to not reach a palindrome under the "Reverse and Add" iteration. Cf A193241, the trajectory of 10100 (decimal 20). %K A193240 nonn,base %O A193240 0,1 %A A193240 _Kerry Mitchell_, Jul 19 2011