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 A116229 #12 Jul 18 2021 02:49:18 %S A116229 8,98,998,9998,99998,999998,9999998,99999998,999999998,9999999998, %T A116229 36363636361,45454545452,54545454543,63636363634,72727272725, %U A116229 81818181816,90909090907,99999999998,999999999998,9999999999998 %N A116229 Numbers k such that k*(k+6) gives the concatenation of two numbers m and m-9. %e A116229 99999998 * 100000004 = 100000001//99999992, where // denotes concatenation. %Y A116229 Cf. A099150, A116098, A116228, A116230, A116237. %K A116229 nonn,base %O A116229 1,1 %A A116229 _Giovanni Resta_, Feb 06 2006