login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
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

Index entries for sequences related to Reverse and Add!

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

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

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