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 A116347 #2 Mar 30 2012 17:40:41 %S A116347 345,647,829,878,933,33180,42271,57721,66812,316429537030539, %T A116347 319485532390187,328611858418903,332707864512186,339600869407914, %U A116347 347417506407134,355879196889561,370588838784509,383811170906508 %N A116347 n times n+9 gives the concatenation of two numbers m and m+8. %e A116347 66812 * 66821 = 44644//44652, where // denotes concatenation. %Y A116347 Cf. A116216, A116342, A116346, A116355. %K A116347 nonn,base %O A116347 1,1 %A A116347 _Giovanni Resta_, Feb 06 2006