A015980 Four iterations of Reverse and Add are needed to reach a palindrome.

69, 78, 87, 96, 174, 175, 181, 183, 191, 192, 195, 273, 274, 280, 282, 290, 291, 294, 372, 373, 381, 390, 393, 471, 472, 480, 492, 539, 570, 571, 579, 591, 599, 629, 638, 649, 670, 678, 679, 690, 698, 699, 728, 729, 737, 748, 749, 769, 777

Offset

0,1

Comments

The number of iterations starts at 1, so palindromes (cf. A002113) are not excluded. The corresponding sequence excluding palindromes is A065209.

Links

Harvey P. Dale, Table of n, a(n) for n = 0..1000

Index entries for sequences related to Reverse and Add!

Mathematica

ra4Q[n_]:=With[{c=Rest[NestList[#+IntegerReverse[#]&, n, 4]]}, PalindromeQ[ Last[c]] && NoneTrue[Most[c], PalindromeQ]]; Select[Range[800], ra4Q] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, May 28 2018 *)

Crossrefs

A002113, A065209.

Sequence in context: A295806 A210614 A235226 * A065209 A045021 A254712

Adjacent sequences: A015977 A015978 A015979 * A015981 A015982 A015983

Keyword

nonn,base

Author

Robert G. Wilson v

Status

approved