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 A138469 #14 Apr 18 2013 02:50:51 %S A138469 5,6,7,8,9,10,13,14,15,16,17,18,31,32,33,34,35,36,49,50,51,52,53,54, %T A138469 81,82,83,84,85,86,113,114,115,116,117,118 %N A138469 Atomic numbers of p-block elements. %C A138469 6 X 6 square of orbital p filling elements in Mendeleyev-Seaborg or Janet-Tarantola periodic table. %C A138469 The sequence is considered full if we assume that all elements with 8 shells or more, i.e. of periods 8 and higher in Mendeleev's periodic table, have extremely unstable nuclei (extremely short half-life.) %C A138469 The atomic numbers of elements in each block are %C A138469 s-block: 1,2, 3,4, 11,12, 19,20, 37,38, 55,56, 87,88 for Mendeleev's periodic table (Cf. A160914) %C A138469 s-block: 1,2, 3,4, 11,12, 19,20, 37,38, 55,56, 87,88, 119,120 for Janet's periodic table (Cf. A160914) %C A138469 p-block: 5..10, 13..18, 31..36, 49..54, 81..86, 113..118 (Cf. A138469) %C A138469 d-block: 21..30, 39..48, 71..80, 103..112 (Cf. A199934) %C A138469 f-block: 57..70, 89..102 (Cf. A217923) %H A138469 OEIS Wiki, <a href="/wiki/Periodic_table">Periodic table</a> %Y A138469 Cf. A130517, A131603, A167268. %Y A138469 Cf. A160914 Atomic numbers of s-block elements. %Y A138469 Cf. A138469 Atomic numbers of p-block elements. %Y A138469 Cf. A199934 Atomic numbers of d-block elements. %Y A138469 Cf. A217923 Atomic numbers of f-block elements. %K A138469 nonn,tabf,fini,full %O A138469 1,1 %A A138469 _Paul Curtz_, May 09 2008 %E A138469 Edited by _Daniel Forgues_, May 15 2011 %E A138469 Ref. to A160914 and A199934 inserted by _Jean-François Alcover_, Oct 15 2012