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 A142716 #5 Mar 30 2012 18:51:59 %S A142716 1,1,1,3,3,3,3,6,6,9,9,18,18,18,45,36,45,99,81,108,216,189,243,486, %T A142716 432,540,1107,972,1215,2511,2187,2754,5670,4941,6237,12798,11178, %U A142716 14094,28917,25272,31833,65367,57105,71928,147744,129033,162567 %N A142716 First differences of A140495. %F A142716 3 | a(n), n>3. %K A142716 nonn %O A142716 1,4 %A A142716 _Paul Curtz_, Sep 26 2008