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 A217212 #8 Oct 01 2012 21:01:33 %S A217212 0,0,2,2,4,10,20,38,82,164,328,660,1320,2640,5304,10596,21192,42424, %T A217212 84848,169668,339428,678856,1357712,2715548,5431096,10862192,21724746, %U A217212 43449380,86898760,173798220,347596440,695192670 %N A217212 Number of sequences of 2's and 3's of length n with curling number 3. %Y A217212 Column 3 of A216955. Cf. A122536, A217211. %K A217212 nonn %O A217212 1,3 %A A217212 _N. J. A. Sloane_, Oct 01 2012