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 A037042 #23 Sep 03 2018 22:54:49 %S A037042 0,1,45,55,99 %N A037042 2-White numbers (take power 2, sum 2-digit groups to get same number). %C A037042 Also, apart from initial 0, the full list of 2-Kaprekar numbers. %D A037042 Italo Ghersi, Matematica dilettevole e curiosa, p. 190, Hoepli, Milano, 1967. [_Vincenzo Librandi_, Apr 22 2010] %H A037042 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 A037042 <a href="/index/Coi#Colombian">Index entries for Colombian or self numbers and related sequences</a> %e A037042 45 is a 2-White number since 45^2 = 2025 and 20 + 25 = 45. %K A037042 full,nonn,fini,base %O A037042 1,3 %A A037042 _Erich Friedman_ %E A037042 Offset set to 1 by _Paolo P. Lava_, Jul 12 2016