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 A116256 #9 Jul 18 2021 02:54:53 %S A116256 6,96,450,545,688,853,996,4379,5616,9996,72727,99996,346530,653465, %T A116256 999996,9090905,9999996,94117643,99999996,334665330,336032384, %U A116256 378253325,390977439,439928488,483516483,516483512,560071507 %N A116256 Numbers k such that k*(k+6) gives the concatenation of two numbers m and m-5. %Y A116256 Cf. A116125, A116242, A116255, A116257, A116262. %K A116256 nonn,base %O A116256 1,1 %A A116256 _Giovanni Resta_, Feb 06 2006