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 A046486 #19 Jan 31 2020 12:06:17 %S A046486 1,2,3,12,16,47,314 %N A046486 Numbers k such that the sum of the first k palindromes is a palindrome. %H A046486 Patrick De Geest, <a href="http://www.worldofnumbers.com/index.html">World!Of Numbers</a> %e A046486 a(n)=47 so 1+2+3+...+373+383 (47 terms) = 7557. %t A046486 palQ[n_] := Reverse[x = IntegerDigits[n]] == x; t = Select[Range[25000], palQ[#] &]; Flatten[Rest[Position[Accumulate[t], _?palQ]]] (* _Jayanta Basu_, Jun 26 2013 *) %t A046486 Position[Accumulate[Select[Range[100000],PalindromeQ]],_?PalindromeQ] // Flatten (* Requires Mathematica version 10 or later *) (* _Harvey P. Dale_, Jan 31 2020 *) %Y A046486 Cf. A002113, A046487, A046488. %K A046486 nonn,hard,base %O A046486 1,2 %A A046486 _Patrick De Geest_, Sep 15 1998