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 A046264 #7 Oct 10 2019 00:36:41 %S A046264 1,6,6,6,9,777,656,99,616,696,66,797,767,606,9,9,282,444,5995,9,656, %T A046264 77,131,22,838,2992,9,77,464,89298,919,656,39193,666,18381,7997,949, %U A046264 909,929,797,43734,703307,515,288737882,19191,404,919,595,21112,434,74647 %N A046264 Largest palindromic substring in 6^n. %Y A046264 Cf. A046272. %K A046264 nonn,base %O A046264 0,2 %A A046264 _Patrick De Geest_, Jun 15 1998