
 Palindromic number  Wikipedia, the free encyclopedia 
  It is fairly straightforward to appreciate that in any base there are infinitely many palindromic numbers, since in any base the infinite sequence of numbers written (in that base) as 101, 1001, 10001, etc. (in which the nth number is a 1, followed by n zeroes, followed by a 1) consists of palindromic numbers only. 
  All numbers in base 10 with one digit {0, 1, 2, 3, 4, 5, 6, 7, 8, 9} are palindromic ones. 
  or in decimal: 0, 1, 3, 5, 7, 9, 15, 17, 21, 27, 31, 33, … (sequence A006995 in OEIS). 
 en.wikipedia.org /wiki/Palindromic_number (745 words) 
