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 A116353 #6 Jul 16 2021 21:34:02 %S A116353 27,67,3416102887775247376839416334668636, %T A116353 3756559953325598880263233435801765,4313503800489302411917772257282209 %N A116353 Numbers k such that k*(k+7) gives the concatenation of two numbers m and m+9. %e A116353 67 * 74 = 49//58, where // denotes concatenation. %Y A116353 Cf. A116169, A116346, A116352, A116354. %K A116353 nonn,base %O A116353 1,1 %A A116353 _Giovanni Resta_, Feb 06 2006