%I A023108
%S A023108 196,295,394,493,592,689,691,788,790,879,887,978,986,1495,1497,1585,1587,
%T A023108 1675,1677,1765,1767,1855,1857,1945,1947,1997,2494,2496,2584,2586,2674,
%U A023108 2676,2764,2766,2854,2856,2944,2946,2996,3493,3495,3583,3585,3673,3675
%N A023108 Positive integers which apparently never result in a palindrome under 
               repeated applications of the function f(x) = x + (x with digits reversed).
%C A023108 Also called Lychrel numbers.
%C A023108 The definition of "Lychrel number" varies: Purists only call the "seeds" 
               or "root numbers" Lychrel; the "related" or "extra" numbers (arising 
               in the former's orbit) have been coined "Kin numbers" by Koji Yamashita. 
               There are only 2 "root" Lycherels below 1000 and 3 more below 10000, 
               cf. A088753. - M. F. Hasler, Dec 04 2007
%D A023108 F. Gruenberger, Computer Recreations, Scientific American, 250 (No. 4, 
               1984), 19-26.
%D A023108 R. K. Guy, What's left?, preprint, 1998.
%H A023108 P. De Geest, <a href="http://www.worldofnumbers.com/weblinks.htm">Some 
               thematic websources</a>
%H A023108 Jason Doucette, <a href="http://www.jasondoucette.com/worldrecords.html">
               World Records</a>
%H A023108 T. Irvin, <a href="http://www.fourmilab.ch/documents/threeyears/two_months_more.html">
               About Two Months of Computing, or An Addendum to Mr. Walker's Three 
               Years of Computing</a>
%H A023108 N. N., <a href="http://www.p196.org/">www.p196.org</a>
%H A023108 Project Euler, <a href="http://projecteuler.net/index.php?section=problems&id=55">
               Problem 55: How many Lychrel numbers are there below ten-thousand?</
               a>
%H A023108 Wade VanLandingham, <a href="http://web.archive.org/web/20030828235934/
               http://home.cfl.rr.com/p196/lychrel.html">Largest known Lychrel number</
               a>
%H A023108 J. Walker, <a href="http://www.fourmilab.ch/documents/threeyears/threeyears.html">
               Three Years Of Computing: Final Report On The Palindrome Quest</a>
%H A023108 Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/
               196-Algorithm.html">Link to a section of The World of Mathematics.</
               a>
%H A023108 Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/
               PalindromicNumberConjecture.html">Link to a section of The World 
               of Mathematics.</a>
%H A023108 Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/
               196-Algorithm.html">196-Algorithm</a>
%H A023108 Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/
               LychrelNumber.html">Lychrel Number</a>
%H A023108 <a href="Sindx_Res.html#RAA">Index entries for sequences related to Reverse 
               and Add!</a>
%Y A023108 Cf. A006960, A088753, A063048, A089694, A089521.
%Y A023108 Sequence in context: A151713 A118781 A119667 this_sequence A092231 A089493 
               A088753
%Y A023108 Adjacent sequences: A023105 A023106 A023107 this_sequence A023109 A023110 
               A023111
%K A023108 nonn,base,nice
%O A023108 1,1
%A A023108 David W. Wilson (davidwwilson(AT)comcast.net)
%E A023108 196 is conjectured to be smallest initial term which does not lead to 
               a palindrome. John Walker, Tim Irvin and others have extended this 
               to millions of digits without finding one.
%E A023108 Edited by M. F. Hasler (maximilian.hasler(AT)gmail.com), Dec 04 2007