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 A101648 #5 Apr 27 2011 13:03:21 %S A101648 5,14,32,33,51,52,84 %N A101648 Atomic numbers of the metalloids or semimetals on the periodic table. %C A101648 If ununhexium and ununseptium turn out to be metalloids, 116 and 117 should be added to this sequence, so I'm not putting the keyword full at this time. The metalloids are sandwiched between the nonmetals and the poor metals on the periodic table. %D A101648 The New Encyclopaedia Britannica, 15th Edition, 1991, Volume 15 (Macropedia), Chemical Elements. %H A101648 Wikipedia, <a href="http://en.wikipedia.org/wiki/Periodic_table">Periodic table</a>. %H A101648 Wikipedia, <a href="http://en.wikipedia.org/wiki/Metalloid">Metalloids</a>. %e A101648 The atomic number of boron is 5. %Y A101648 Cf. A099955, alkali metals; A099956, alkaline earth metals; A101647, nonmetals (except halogens and noble gases); A097478, halogens; A018227, noble gases; A101649, poor metals. %K A101648 fini,nonn %O A101648 1,1 %A A101648 Robert Happelberg (roberthappelberg(AT)yahoo.com), Dec 10 2004