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 A061563 Start with n; add to itself with digits reversed; if palindrome, stop; otherwise repeat; a(n) gives palindrome at which it stops, or -1 if no palindrome is ever reached. 8
 0, 2, 4, 6, 8, 11, 33, 55, 77, 99, 11, 22, 33, 44, 55, 66, 77, 88, 99, 121, 22, 33, 44, 55, 66, 77, 88, 99, 121, 121, 33, 44, 55, 66, 77, 88, 99, 121, 121, 363, 44, 55, 66, 77, 88, 99, 121, 121, 363, 484, 55, 66, 77, 88, 99, 121, 121, 363, 484, 1111, 66, 77, 88, 99, 121 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 COMMENTS It is believed that n = 196 is the smallest integer which never reaches a palindrome. LINKS T. D. Noe, Table of n, a(n) for n=0..195 EXAMPLE 19 -> 19 + 91 = 110 -> 110 + 011 = 121, so a(19) = 121. MATHEMATICA tol = 1000; r[n_] := FromDigits[Reverse[IntegerDigits[n]]]; palQ[n_] := n == r[n]; ar[n_] := n + r[n]; Table[k = 0; If[palQ[n], n = ar[n]; k = 1]; While[! palQ[n] && k < tol, n = ar[n]; k++]; If[k == tol, n = -1]; n, {n, 0, 64}] (* Jayanta Basu, Jul 11 2013 *) Table[Module[{k=n+IntegerReverse[n]}, While[k!=IntegerReverse[k], k=k+IntegerReverse[k]]; k], {n, 0, 70}] (* The program uses the IntegerReverse function from Mathematica version 10 *) (* Harvey P. Dale, Jul 19 2016 *) PROG (ARIBAS): var st: stack; test: boolean; end; for k := 0 to 60 do n := k; test := true; while test do n := n + int_reverse(n); test := n <> int_reverse(n); end; stack_push(st, n); end; stack2array(st). CROSSREFS Cf. A033865. A016016 (number of steps), A023109, A006950, A023108. Sequence in context: A247123 A068062 A088169 * A099994 A068065 A278228 Adjacent sequences:  A061560 A061561 A061562 * A061564 A061565 A061566 KEYWORD nonn,base,easy,nice,look AUTHOR N. J. A. Sloane, May 18 2001 EXTENSIONS Corrected and extended by Klaus Brockhaus, May 20 2001 More terms from Ray Chandler, Jul 25 2003 STATUS approved

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Last modified October 22 03:04 EDT 2019. Contains 328315 sequences. (Running on oeis4.)