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 A027728 #16 Aug 04 2025 12:36:29
%S A027728 5,7,11,77,161,707,5555,16261,50405,53135,7570757,11988911,16100161,
%T A027728 16544561,162626261,502858205,758919857,793464397,11092829011,
%U A027728 11539593511,5560873780655,7424090904247,7702753572077,16515222251561,57293477439275,7246424554246427
%N A027728 Palindromes of form k^2 + k + 5.
%H A027728 Giovanni Resta, <a href="/A027728/b027728.txt">Table of n, a(n) for n = 1..46</a>
%H A027728 P. De Geest, <a href="https://www.worldofnumbers.com/quasimor.htm">Palindromic Quasi_Over_Squares of the form n^2+(n+X)</a>
%t A027728 palQ[n_] := Block[{d = IntegerDigits[n]}, d == Reverse[d]]; f[n_] := n^2 + n + 5; Select[f@ Range[0, 10^5], palQ] (* _Giovanni Resta_, Aug 29 2018 *)
%t A027728 Select[Table[k^2+k+5,{k,0,852*10^5}],PalindromeQ] (* _Harvey P. Dale_, Aug 04 2025 *)
%Y A027728 Cf. A027718, A027690, A027754, A027755, A027717, A027728, A027721.
%K A027728 nonn,base
%O A027728 1,1
%A A027728 _Patrick De Geest_
%E A027728 More terms from _Giovanni Resta_, Aug 28 2018