A086918 - OEIS

A086918

Numbers with at least three digits such that the absolute differences between successive digits forms a palindrome (when leading zeros are omitted).

101, 110, 111, 112, 113, 114, 115, 116, 117, 118, 119, 121, 123, 131, 135, 141, 147, 151, 159, 161, 171, 181, 191, 202, 210, 212, 220, 221, 222, 223, 224, 225, 226, 227, 228, 229, 232, 234, 242, 246, 252, 258, 262, 272, 282, 292, 303, 313, 321, 323, 330, 331

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,1

COMMENTS

All numbers from 0 to 99 trivially have the property, so we require at least three digits.

Question: There seems to be a pattern. Can someone find a formula for index of a given member?

LINKS

Harvey P. Dale, Table of n, a(n) for n = 1..1000

EXAMPLE

112 is a member yielding (0)2.

131 and 135 both are members and the palindrome arising in both cases is 22.

MATHEMATICA

Select[Range[100, 500], PalindromeQ[FromDigits[Abs[ Differences[ IntegerDigits[ #]]]]]&] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Nov 14 2019 *)

CROSSREFS

Cf. A086919.

Sequence in context: A107219 A366106 A140799 * A259300 A025349 A025341

Adjacent sequences: A086915 A086916 A086917 * A086919 A086920 A086921

KEYWORD

base,easy,nonn

AUTHOR

Amarnath Murthy, Sep 18 2003

EXTENSIONS

Corrected and extended by Harvey P. Dale, Nov 14 2019

STATUS

approved