Numbers whose reciprocals have a palindromic repeating part in base 9.
2, 4, 8, 12, 18, 24, 36, 72, 108, 162, 216, 324, 648, 972, 1458, 1944, 2916, 5832, 8748, 13122, 17496, 26244, 52488, 78732, 118098, 157464, 236196, 472392
1
All palindromes appear to be just one digit. These numbers appear to be (2, 4, 8, 12, 24) * 9^(i-1) for i = 1, 2, 3,… sorted.
T. D. Noe, Plot of 28 terms
Wikipedia, Repeating decimal
(Mma) Select[Range[9^4], (r = RealDigits[1/#, 9]; ! IntegerQ[r[[1, 1]]] && r[[1, 1]] == Reverse[r[[1, 1]]]) &]
nonn,base
T. D. Noe, Jun 03 2016