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 A028554 #15 Aug 11 2024 14:41:29 %S A028554 0,4,88,868,4554,8008,45154,89698,452254,4526254,8996998,830333038, %T A028554 862626268,899969998,4058008504,45032023054,45229592254,89999699998, %U A028554 405485584504,4503764673054,8187727277818,8999996999998,89178266287198,455467838764554,833066101660338 %N A028554 Palindromes of form n(n+3). %C A028554 Also: Palindromes that are the sum of consecutive initial even composites. Sequence 4 + 6 + 8 + 10 + 12 + 14 + ... + z = n. For values of z see A058851. (Comment added by author 12/2000). %C A028554 9*10^(2n)-3*10^n-2 for n >= 0 are terms. For n > 1, the first (and last digit) of a(n) is either 4 or 8. - _Chai Wah Wu_, Feb 20 2021 %H A028554 Chai Wah Wu, <a href="/A028554/b028554.txt">Table of n, a(n) for n = 1..40</a> %H A028554 P. De Geest, <a href="https://www.worldofnumbers.com/consemor.htm">Palindromic Quasipronics</a> %H A028554 P. De Geest, <a href="https://www.worldofnumbers.com/firstpal.htm#sfn5">Palindromic Sums 2</a> %o A028554 (Python) %o A028554 n, m, A028554_list = 4, 0, [] %o A028554 while n < 10**12: %o A028554 s = str(m) %o A028554 if s == s[::-1]: %o A028554 A028554_list.append(m) %o A028554 m += n %o A028554 n += 2 # _Chai Wah Wu_, Feb 20 2021 %Y A028554 Cf. A028553, A058851. %K A028554 nonn,base %O A028554 1,2 %A A028554 _Patrick De Geest_ %E A028554 More terms from _Chai Wah Wu_, Feb 20 2021