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 A030148 #8 May 15 2021 17:50:36 %S A030148 1,3,5,7,9,101,121,141,161,181,303,323,343,363,383,505,525,545,565, %T A030148 585,707,727,747,767,787,909,929,949,969,989,10101,10301,10501,10701, %U A030148 10901,12121,12321,12521,12721,12921,14141,14341,14541,14741 %N A030148 Odd palindromes in which parity of digits alternates. %H A030148 Matthew House, <a href="/A030148/b030148.txt">Table of n, a(n) for n = 1..10000</a> %t A030148 apQ[n_]:=And@@(#[[1]]!=#[[2]]&/@Partition[Boole[EvenQ[ IntegerDigits[ n]]],2,1]); Select[Range[1,15000,2],PalindromeQ[#]&&apQ[#]&] (* Requires Mathematica version 10 or later *) (* _Harvey P. Dale_, May 15 2021 *) %K A030148 nonn,base %O A030148 1,2 %A A030148 _Patrick De Geest_