A015990 Nine iterations of Reverse and Add are needed to reach a palindrome.

1397, 1487, 1577, 1667, 1757, 1847, 1937, 2396, 2486, 2576, 2666, 2756, 2846, 2936, 2999, 3395, 3485, 3575, 3665, 3755, 3845, 3935, 3998, 4394, 4484, 4574, 4664, 4754, 4844, 4934, 4997, 5393, 5483, 5573, 5663, 5753, 5843, 5933, 5996, 6392, 6482, 6572, 6662, 6752, 6842, 6932, 6995

Offset

1,1

Comments

The number of iterations starts at 1, so palindromes (cf. A002113) are not excluded. The corresponding sequence excluding palindromes is A065214.

Links

Table of n, a(n) for n=1..47.

Index entries for sequences related to Reverse and Add!

Mathematica

ra9Q[n_]:=Length[NestWhileList[#+FromDigits[Reverse[IntegerDigits[ #]]]&, n, IntegerDigits[ #]!= Reverse[IntegerDigits[#]]&, 1, 10]]==10; Select[ Range[ 7000], ra9Q] (* Harvey P. Dale, Mar 08 2015 *)

Crossrefs

Cf. A002113.

Different from A065214.

Sequence in context: A069366 A163054 A110844 * A065214 A336738 A271549

Adjacent sequences: A015987 A015988 A015989 * A015991 A015992 A015993

Keyword

nonn,base

Author

Robert G. Wilson v

Extensions

Corrected and extended by Harvey P. Dale, Mar 08 2015

Missing a(27)=4664 inserted by Sean A. Irvine, Dec 20 2018

Offset set to 1 by Alois P. Heinz, Dec 20 2018

Status

approved