A061917 Either a palindrome or becomes a palindrome if trailing 0's are omitted.

0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 20, 22, 30, 33, 40, 44, 50, 55, 60, 66, 70, 77, 80, 88, 90, 99, 100, 101, 110, 111, 121, 131, 141, 151, 161, 171, 181, 191, 200, 202, 212, 220, 222, 232, 242, 252, 262, 272, 282, 292, 300, 303, 313, 323, 330, 333, 343, 353, 363, 373, 383, 393, 400, 404

Offset

1,3

Comments

Numbers that are palindromes when written with a suitable number of leading zeros. - Jeppe Stig Nielsen, Jan 17 2022

Links

Reinhard Zumkeller, Table of n, a(n) for n = 1..10000

Formula

A136522(A004151(a(n))) = 1. - Reinhard Zumkeller, Sep 25 2011

Mathematica

PaleQ[n_Integer, base_Integer] := Module[{idn, trim = n/base^IntegerExponent[n, base]}, idn = IntegerDigits[trim, base]; idn == Reverse[idn]]; Select[Range[0, 500], PaleQ[#, 10] &] (* Lei Zhou, Dec 13 2013 *)
Join[{0}, Select[Range[500], PalindromeQ[FromDigits[Drop[IntegerDigits[#], -IntegerExponent[#, 10]]]]&]] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, May 27 2017 *)

Prog

(Haskell)
a061917 n = a061917_list !! (n-1)
a061917_list = filter chi [0..] where
   chi x = zs == reverse zs where
      zs = dropWhile (== '0') $ reverse $ show x
-- Reinhard Zumkeller, Sep 25 2011
(PARI) isOK(k)=k==0||fromdigits(Vecrev(digits(k)))==k/10^valuation(k, 10) \\ Jeppe Stig Nielsen, Jan 17 2022
(Python)
def ispal(s): return s == s[::-1]
def ok(n): s = str(n); return ispal(s) or ispal(s.rstrip('0'))
print([k for k in range(405) if ok(k)]) # Michael S. Branicky, Jan 17 2022

Crossrefs

Cf. A002113, A057890, A057891.

Sequence in context: A281625 A169824 A325152 * A125289 A180482 A193460

Adjacent sequences: A061914 A061915 A061916 * A061918 A061919 A061920

Keyword

nonn,base,easy,nice

Author

N. J. A. Sloane, Jun 27 2001

Extensions

Corrected by Ray Chandler, Jun 08 2009

Status

approved