0,1

a(1) = 196; a(n+1) = a(n) + a(n)-with-digits-reversed.

F. Gruenberger, Computer Recreations, Scientific American, 250 (No. 4, 1984), 19-26.

R. K. Guy, What's left?, preprint, 1998.

Clifford A. Pickover, A Passion for Mathematics, Wiley, 2005; see p. 70.

J.-M. De Koninck, Ces nombres qui nous fascinent, Entry 196, p. 58, Ellipses, Paris 2008.

T. D. Noe, Table of n, a(n) for n=0..200

P. De Geest, Some thematic websources

Jason Doucette, World Records

T. Irvin, About Two Months of Computing, or An Addendum to Mr. Walker's Three Years of Computing

Madras Math's Amazing Number Facts, The Ultimate Palindrome

I. Peter, More trajectories

Wade VanLandingham, 196

J. Walker, Three Years Of Computing: Final Report On The Palindrome Quest

Eric Weisstein's World of Mathematics, Link to a section of The World of Mathematics.

Eric Weisstein's World of Mathematics, Link to a section of The World of Mathematics.

Index entries for sequences related to Reverse and Add!

a = {196}; For[i = 2, i < 26, i++, a = Append[a, a[[i - 1]] + ToExpression[ StringReverse[ToString[a[[i - 1]]]]]]]; a

Cf. A023108, A023109, A033665, A016016.

Adjacent sequences: A006957 A006958 A006959 this_sequence A006961 A006962 A006963

Sequence in context: A089493 A088753 A063048 this_sequence A014798 A061622 A128990

nonn,base,nice,easy

njas, Simon Plouffe (plouffe(AT)math.uqam.ca)

196 is conjectured to be smallest initial term which does not lead to a palindrome. John Walker, Tim Irvin and others have extended the trajectory of 196 to millions of digits without finding a palindrome.

More terms from Vit Planocka (planocka(AT)mistral.cz), Sep 28 2002