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 A116153 #6 Jul 20 2021 23:45:32 %S A116153 13,41,653,2287,2723,5491,23240971,26823191,60249661,1841968537, %T A116153 2009317771,3044234903,3258336353,8166731261,9481619237, %U A116153 1281071245505271100098621541,1551605670846640136726379653 %N A116153 Numbers k such that k concatenated with k-1 gives the product of two numbers which differ by 9. %Y A116153 Cf. A116147, A116152, A116162, A116284. %K A116153 nonn,base %O A116153 1,1 %A A116153 _Giovanni Resta_, Feb 06 2006