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 A217427 #9 Sep 07 2014 08:39:14 %S A217427 20,38,45,48,38,35,650 %N A217427 7-adic valuation of A217425. %C A217427 A217425 consists of numbers of the form (5^r)*(7^s). This sequence holds the s values. %Y A217427 Cf. A217425, A217426. %K A217427 nonn,base,less %O A217427 1,1 %A A217427 _James G. Merickel_, Oct 03 2012