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

Author

Robert G. Wilson v

Keywords

• nonn
• base

Comments

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

Links

• Index entries for sequences related to Reverse and Add!

Crossrefs

Cf. A002113.

Different from A065214.

Programs

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 *)

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