A043037 Base-10 palindromes that start with 2.

2, 22, 202, 212, 222, 232, 242, 252, 262, 272, 282, 292, 2002, 2112, 2222, 2332, 2442, 2552, 2662, 2772, 2882, 2992, 20002, 20102, 20202, 20302, 20402, 20502, 20602, 20702, 20802, 20902, 21012, 21112, 21212, 21312, 21412, 21512, 21612, 21712, 21812, 21912

Offset: 1

Author

Clark Kimberling

Keywords

• nonn
• base

Links

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

Crossrefs

Cf. A002113.

Programs

Mathematica

palQ[n_Integer, base_Integer] := Module[{idn = IntegerDigits[n, base]}, idn == Reverse[idn]]; Select[Range[0, 100000], IntegerDigits[#][[1]] == 2 && palQ[#, 10] &] (* T. D. Noe, Mar 12 2013 *)
Select[Range[22000],PalindromeQ[#]&&IntegerDigits[#][[1]]==2&] (* Harvey P. Dale, Feb 21 2024 *)

PARI

isok(n) = (d=digits(n)) && (d[1]==2) && (Vecrev(d)==d); \\ Michel Marcus, Aug 22 2015