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 A027716 #18 Aug 11 2024 14:41:29
%S A027716 0,1,20,200,219,261,2000,2234,2551,2613,20000,20604,200000,202885,
%T A027716 205704,218354,2000000,2155139,2490266,2620486,20000000,25882353,
%U A027716 200000000,205705704,2000000000,2094600194,20000000000,20102030400,20349812814,21572321960
%N A027716 Numbers k such that k^2 + k + 4 is a palindrome.
%C A027716 Includes 2*10^k for k>=2. - _Robert Israel_, Apr 16 2019
%H A027716 Giovanni Resta, <a href="/A027716/b027716.txt">Table of n, a(n) for n = 1..36</a>
%H A027716 P. De Geest, <a href="https://www.worldofnumbers.com/quasimor.htm">Palindromic Quasi_Over_Squares of the form n^2+(n+X)</a>
%t A027716 palQ[n_] := Block[{d = IntegerDigits[n]}, d == Reverse[d]]; f[n_] := n^2 + n + 4; Select[Range[0, 10^5], palQ@ f@ # &] (* _Giovanni Resta_, Aug 29 2018 *)
%t A027716 Select[Range[0,3*10^6],PalindromeQ[#^2+#+4]&] (* The program generates the first 20 terms of the sequence. *) (* _Harvey P. Dale_, Jul 22 2024 *)
%Y A027716 Cf. A027717, A027689, A027714, A027718.
%K A027716 nonn,base
%O A027716 1,3
%A A027716 _Patrick De Geest_
%E A027716 More terms from _Giovanni Resta_, Aug 29 2018