A121233 Palindromes whose ten's complements are squares.

1, 6, 9, 99, 424, 676, 919, 999, 4224, 5775, 9559, 9999, 57975, 63136, 91719, 93439, 99999, 951159, 999999, 1196911, 4402044, 6359536, 6944496, 9173719, 9329239, 9959599, 9977799, 9999999, 67144176, 99188199, 99999999, 577080775, 915525519

Offset

1,2

Comments

Known primes occurring in the sequence are 919, 1196911, 9173719 and 9329239.

Links

Table of n, a(n) for n=1..33.

Example

424 is a term because it's palindromic and 10^3-424 = 576 = 24^2.

Mathematica

Select[Range[10^6], PalindromeQ[#]&&IntegerQ[Sqrt[10^(Ceiling[Log10[#]])-#]]&] (* James C. McMahon, Oct 16 2024 *)

Crossrefs

Sequence in context: A103107 A370623 A377683 * A156180 A191011 A351734

Adjacent sequences: A121230 A121231 A121232 * A121234 A121235 A121236

Keyword

base,nonn

Author

Jason Earls, Aug 21 2006

Extensions

More terms from R. J. Mathar, Sep 02 2006

Status

approved