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 A116308 #7 Jul 17 2021 01:44:05 %S A116308 452,547,690,855,4381,5618,72729,346532,653467,9090907,94117645, %T A116308 334665332,336032386,378253327,390977441,439928490,483516485, %U A116308 516483514,560071509,609022558,621746672,663967613,665334667 %N A116308 Numbers k such that k*(k+2) is the concatenation of two numbers m and m+3. %Y A116308 Cf. A116177, A116295, A116307, A116309, A116315. %K A116308 nonn,base %O A116308 1,1 %A A116308 _Giovanni Resta_, Feb 06 2006