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 A217412 #9 Sep 07 2014 08:22:08 %S A217412 10,9,34,8,20,7,8,8,15,14,1,26,39,20,6,57,949 %N A217412 7-adic valuation of A217410. %C A217412 These are the values s for numbers of the form (3^r)*(7^s) in the main sequence. %e A217412 A217410(1)=(3^37)*(7^10), so this sequence's first term is 10. %Y A217412 Cf. A217410, A217411. %K A217412 nonn,base,less %O A217412 1,1 %A A217412 _James G. Merickel_, Oct 02 2012