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 A207954 #12 Feb 16 2021 14:18:32
%S A207954 1,2,3,4,5,6,7,8,9,101,121,212,232,323,343,434,454,545,565,656,676,
%T A207954 767,787,878,898,989,10101,12121,12321,21012,21212,23232,23432,32123,
%U A207954 32323,34343,34543,43234,43434,45454,45654,54345,54545,56565,56765,65456,65656
%N A207954 Palindromes with consecutive digits that differ exactly by 1.
%H A207954 Reinhard Zumkeller, <a href="/A207954/b207954.txt">Table of n, a(n) for n = 1..10000</a>
%t A207954 Join[Range[9],Select[Range[70000],Union[Abs[Differences[ IntegerDigits[ #]]]] == {1}&&PalindromeQ[#]&]] (* Requires Mathematica version 10 or later *) (* _Harvey P. Dale_, Feb 16 2021 *)
%o A207954 (Haskell)
%o A207954 a207954 n = a207954_list !! (n-1)
%o A207954 a207954_list = filter ((== 1) . a136522) a033075_list
%Y A207954 Cf. A136522; intersection of A033075 and A002113.
%K A207954 nonn,base
%O A207954 1,2
%A A207954 _Reinhard Zumkeller_, Feb 21 2012