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 A116274 #9 Jul 18 2021 03:01:57 %S A116274 9,99,362,636,713,922,999,8904,9999,81817,99999,336632,663366,999999, %T A116274 7272726,9999999,76470588,99999999,333666332,405436667,428571428, %U A116274 447710184,454545453,473684210,526315788,545454545,552289814 %N A116274 Numbers k such that k*(k+3) gives the concatenation of two numbers m and m-2. %Y A116274 Cf. A116143, A116259, A116273, A116275, A116280. %K A116274 nonn,base %O A116274 1,1 %A A116274 _Giovanni Resta_, Feb 06 2006