login
A043037
Base-10 palindromes that start with 2.
5
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
1,1
LINKS
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 *)
PROG
(PARI) isok(n) = (d=digits(n)) && (d[1]==2) && (Vecrev(d)==d); \\ Michel Marcus, Aug 22 2015
CROSSREFS
Cf. A002113.
Sequence in context: A007613 A346796 A279801 * A058441 A255043 A359856
KEYWORD
nonn,base
STATUS
approved