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 A116169 #8 Jul 20 2021 23:46:40 %S A116169 9,49,1166975893986638437392162264780939, %T A116169 1411174268292962563778302427727571,1860631503683565562655236868895135 %N A116169 Numbers k such that k concatenated with k+1 gives the product of two numbers which differ by 9. %C A116169 Also numbers k such that k concatenated with k+9 gives the product of two numbers which differ by 7. %e A116169 49//50 = 66 * 75, where // denotes concatenation. %e A116169 49//58 = 67 * 74. %Y A116169 Cf. A116162, A116168, A116175, A116300. %Y A116169 Cf. A116215, A116174, A116223, A116353. %K A116169 nonn,base %O A116169 1,1 %A A116169 _Giovanni Resta_, Feb 06 2006 %E A116169 Edited by _N. J. A. Sloane_, Apr 15 2007