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 A028571 #13 Aug 11 2024 14:41:29
%S A028571 0,22,252,2332,20002,26062,29392,63736,68886,2701072,2783872,2884882,
%T A028571 29122192,253080352,289050982,25661316652,237776677732,2393677763932,
%U A028571 215331808133512,218759969957812,225588939885522,235212787212532,636759171957636,682911868119286
%N A028571 Palindromes of form k*(k+9).
%H A028571 Michael S. Branicky, <a href="/A028571/b028571.txt">Table of n, a(n) for n = 1..42</a>
%H A028571 P. De Geest, <a href="https://www.worldofnumbers.com/consemor.htm">Palindromic Quasipronics of the form n(n+x)</a>
%F A028571 a(n) = A028570(n) * (A028570(n) + 9). - _Michael S. Branicky_, Jan 26 2022
%t A028571 Select[Table[k(k+9),{k,0,262*10^5}],PalindromeQ] (* _Harvey P. Dale_, Feb 13 2022 *)
%o A028571 (Python)
%o A028571 from itertools import count, islice
%o A028571 def ispal(n): s = str(n); return s == s[::-1]
%o A028571 def agen():
%o A028571 for k in count(0):
%o A028571 if ispal(k*(k+9)):
%o A028571 yield k*(k+9)
%o A028571 print(list(islice(agen(), 18))) # _Michael S. Branicky_, Jan 26 2022
%Y A028571 Cf. A028569, A028570.
%K A028571 nonn,base
%O A028571 1,2
%A A028571 _Patrick De Geest_
%E A028571 a(22) and beyond from _Michael S. Branicky_, Jan 26 2022