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 A116216 #7 Jul 18 2021 02:50:23 %S A116216 122,424,694,778,878,11012,17872,33322,44644,100127651905364, %T A116216 102071005406644,107985753493528,110694523108262,115328750502614, %U A116216 120698923758154,126650002778762,137336087431654,147311014912628 %N A116216 Numbers k such that k concatenated with k+8 gives the product of two numbers which differ by 9. %e A116216 44644//44652 = 66812 * 66821, where // denotes concatenation. %Y A116216 Cf. A116211, A116215, A116224, A116347. %K A116216 nonn,base %O A116216 1,1 %A A116216 _Giovanni Resta_, Feb 06 2006