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 A058848 #23 Aug 05 2025 18:23:19 %S A058848 1,12,25,61,108,211,1344,2339,10539,78409,283181,1748747,1795423, %T A058848 2386702,2819089,179101605,1923088106,2822581688,7794689270, %U A058848 17381011919,25635268093,28780043265,97973526253 %N A058848 Numbers k such that the sum of the first k odd composites is palindromic. %C A058848 Sequence of odd composite numbers is 9 + 15 + 21 + 25 + 27 + 33 + ... + z. For values of z see A058849. %H A058848 Patrick De Geest, <a href="http://www.worldofnumbers.com/firstpal.htm#sfn4">Palindromic Sums</a> %t A058848 Position[Accumulate[Select[Range[9,10^7,2],CompositeQ]],_?(PalindromeQ[#]&)]//Flatten (* The program generates the first 15 terms of the sequence. *) (* _Harvey P. Dale_, Aug 05 2025 *) %Y A058848 Cf. A058849, A058850, A262044. %K A058848 nonn,base,more %O A058848 1,2 %A A058848 _Patrick De Geest_, Dec 15 2000 %E A058848 a(20) from _Donovan Johnson_, Sep 01 2012 %E A058848 a(21)-a(23) from _Chai Wah Wu_, Dec 06 2019 %E A058848 Comment clarified by _Harvey P. Dale_, Aug 05 2025