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 A116239 #9 Jul 18 2021 02:55:12 %S A116239 7743,8017,33294314,66705679,98000197,340465755421,476452552741, %T A116239 523547447252,659534244572,866013200677,998000001997,3695104677080130, %U A116239 3755782995538764,4198081170077527,4803478892324962,5196521107675031 %N A116239 Numbers k such that k*(k+8) gives the concatenation of two numbers m and m-8. %e A116239 98000197 * 98000205 = 96040393//96040385, where // denotes concatenation. %Y A116239 Cf. A115429, A116238, A116240, A116244. %K A116239 nonn,base %O A116239 1,1 %A A116239 _Giovanni Resta_, Feb 06 2006