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 A194219 #12 Feb 16 2025 08:33:15 %S A194219 0,1,25,25,1,209,209,1,1729,1984,4641,2500,2500,5264,1984,1729,1, %T A194219 14336,17284,37444,17284,14336,4641,1,122449,126201,148761,152100, %U A194219 165025,217124,221089,227904,229449,237969,248521,248900,250000,250000,248900,248521 %N A194219 Right part of the square of the n-th Kaprekar number. %C A194219 A194218(n) + a(n) = A006886(n) and %C A194219 concatenation of A194218(n) and a(n) = A006886(n)^2. %H A194219 Rosetta Code, <a href="http://rosettacode.org/wiki/Kaprekar_numbers">Kaprekar numbers</a> %H A194219 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/KaprekarNumber.html">Kaprekar Number</a> %H A194219 Wikipedia, <a href="http://en.wikipedia.org/wiki/Kaprekar_number">Kaprekar number</a> %o A194219 (Haskell) See A194218. %K A194219 nonn,base %O A194219 1,3 %A A194219 _Reinhard Zumkeller_, Aug 19 2011