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 A214881 #13 May 14 2021 15:29:58 %S A214881 1,2,3,5,5,6,8,8,9,13,14,14,14,14,15,17,17,18,21,21,22,23,26,26,26,26, %T A214881 27,28,30,30,31,32,34,34,36,36,38,38,39,42,41,48,43,44,49,46,47,49,52, %U A214881 51,51,52,53,56,56,56,63,58,59,60,61,65,64,64,66,66,67 %N A214881 2-adic valuation of A016090. %C A214881 a(n) >= n. %C A214881 It appears that the density of n such that a(n) = n is 1/2. %H A214881 Eric M. Schmidt, <a href="/A214881/b214881.txt">Table of n, a(n) for n = 1..10000</a> %H A214881 <a href="/index/Ar#automorphic">Index entries for sequences related to automorphic numbers</a> %o A214881 (GAP) A214881 := function(max) local result, i; result := [6]; for i in [2..max] do Add(result, (2*result[i-1] - result[i-1]^2) mod 10^i); od; result := List(result, x->Valuation(x, 2)); return result; end; %Y A214881 Cf. A016090, A214880, A214882, A214883. %K A214881 nonn,base %O A214881 1,2 %A A214881 _Eric M. Schmidt_, Jul 29 2012