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 A116348 #7 Jul 17 2021 01:44:59 %S A116348 10,90,3678,6322,8788,48745,51255,87619,3762556,6237444,9217102, %T A116348 3266298276,3520463766,6479536234,6733701724,8063694650,8317860140, %U A116348 4689524709430934476,5310475290569065524,7416797436703661749 %N A116348 Numbers k such that k*(k+1) gives the concatenation of two numbers m and m+9. %Y A116348 Cf. A116205, A116343, A116349. %K A116348 nonn,base %O A116348 1,1 %A A116348 _Giovanni Resta_, Feb 06 2006