A043044 Palindromes that start with 9.

9, 99, 909, 919, 929, 939, 949, 959, 969, 979, 989, 999, 9009, 9119, 9229, 9339, 9449, 9559, 9669, 9779, 9889, 9999, 90009, 90109, 90209, 90309, 90409, 90509, 90609, 90709, 90809, 90909, 91019, 91119, 91219, 91319, 91419, 91519, 91619, 91719, 91819, 91919

Offset: 1

Author

Clark Kimberling

Keywords

• nonn
• base
• changed

Comments

Subsequence of A002113 (palindromic numbers). Union of A128375 (palindromic primes starting with a digit 9) and A222729 (palindromic composite numbers starting with a digit 9). - Jaroslav Krizek, Mar 12 2013

Links

• Jaroslav Krizek, Table of n, a(n) for n = 1..2222

Programs

Mathematica

palQ[n_Integer, base_Integer] := Module[{idn = IntegerDigits[n, base]}, idn == Reverse[idn]]; Select[Range[0, 100000], IntegerDigits[#][[1]] == 9 && palQ[#, 10] &] (* T. D. Noe, Mar 12 2013 *)
Select[Range[100000],PalindromeQ[#]&&IntegerDigits[#][[1]]==9&] (* Harvey P. Dale, Oct 13 2022 *)
Join[{9},Table[Select[Flatten[Range[9*10^ex+9,10^(ex+1)-1,10]],PalindromeQ],{ex,4}]]//Flatten (* Harvey P. Dale, Apr 02 2025 *)