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 A053395 #22 Mar 10 2020 10:03:40 %S A053395 1,2223,2728,4950,5050,7272,7777,9999 %N A053395 Complete list of 4-Kaprekar numbers. %H A053395 D. E. Iannucci, <a href="https://cs.uwaterloo.ca/journals/JIS/VOL3/iann2a.html">The Kaprekar numbers</a>, J. Integer Sequences, Vol. 3, 2000, #1.2. %H A053395 <a href="/index/Coi#Colombian">Index entries for Colombian or self numbers and related sequences</a> %Y A053395 Cf. A006886, A037042, A053394, A053396, A053397, A333133. %K A053395 nonn,fini,full,base %O A053395 1,2 %A A053395 _N. J. A. Sloane_, Jan 07 2000