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 A214880 #12 Aug 01 2012 20:37:49 %S A214880 1,2,4,4,5,6,7,8,9,10,11,12,17,14,15,18,17,18,19,20,21,22,23,24,25,26, %T A214880 27,29,29,30,33,33,33,35,35,36,37,38,40,40,41,42,43,44,45,46,47,48,50, %U A214880 51,54,54,54,54,55,56,57,58,59,61,61,63,63,66,66,66,67 %N A214880 5-adic valuation of A007185. %C A214880 a(n) >= n. %C A214880 It appears that the density of n such that a(n) = n is 4/5. %H A214880 Eric M. Schmidt, <a href="/A214880/b214880.txt">Table of n, a(n) for n = 1..10000</a> %H A214880 <a href="/index/Ar#automorphic">Index entries for sequences related to automorphic numbers</a> %o A214880 (GAP) A214880 := function(max) local result, i; result := [5]; for i in [2..max] do Add(result, result[i-1]^2 mod 10^i); od; result := List(result, x->Valuation(x, 5)); return result; end; %Y A214880 Cf. A214881, A214882, A214883. %K A214880 nonn,base %O A214880 1,2 %A A214880 _Eric M. Schmidt_, Jul 29 2012