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 A116197 #6 Jul 19 2021 19:12:54 %S A116197 25,2448207281,2552334847,9492271895,10713024775597019390267617, %T A116197 45251510049471045364918031,99414584492459886818648287, %U A116197 1000584180267191789271991959007645 %N A116197 Numbers k such that k concatenated with k+5 gives the product of two numbers which differ by 9. %Y A116197 Cf. A116190, A116196, A116203, A116328. %K A116197 nonn,base %O A116197 1,1 %A A116197 _Giovanni Resta_, Feb 06 2006