This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A043037 #22 Feb 21 2024 16:55:43
%S A043037 2,22,202,212,222,232,242,252,262,272,282,292,2002,2112,2222,2332,
%T A043037 2442,2552,2662,2772,2882,2992,20002,20102,20202,20302,20402,20502,
%U A043037 20602,20702,20802,20902,21012,21112,21212,21312,21412,21512,21612,21712,21812,21912
%N A043037 Base-10 palindromes that start with 2.
%H A043037 Jaroslav Krizek, <a href="/A043037/b043037.txt">Table of n, a(n) for n = 1..2222</a>
%t A043037 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 *)
%t A043037 Select[Range[22000],PalindromeQ[#]&&IntegerDigits[#][[1]]==2&] (* _Harvey P. Dale_, Feb 21 2024 *)
%o A043037 (PARI) isok(n) = (d=digits(n)) && (d[1]==2) && (Vecrev(d)==d); \\ _Michel Marcus_, Aug 22 2015
%Y A043037 Cf. A002113.
%K A043037 nonn,base
%O A043037 1,1
%A A043037 _Clark Kimberling_