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 A137583 #18 Apr 10 2024 13:14:47
%S A137583 2,2,8,8,18,18,32,32
%N A137583 Number of elements in the n-th period of the Janet periodic table of elements.
%C A137583 Essentially 2 followed by the first terms of A093907.
%C A137583 This puts Hydrogen and Helium in the first row, Lithium and Beryllium into the second, Boron to Magnesium into the third etc.
%H A137583 Mark R. Leach, <a href="https://www.meta-synthesis.com/webbook/35_pt/pt_database.php">The Internet Database of Periodic Tables</a>, Chemogenesis web book.
%H A137583 Albert Tarantola, <a href="https://web.archive.org/web/20230403214915/http://www.ipgp.fr/~tarantola/Files/Professional/Mendeleev/">PSE of Elements (Janet form)</a>.
%H A137583 Mark J. Winter, <a href="https://www.webelements.com/periodic_table_image_long.html">Image of the Janet long format (or 32-column) periodic table</a>, Web Elements Chemistry Nexus.
%t A137583 Flatten@ Table[2 (n #)^2 & /@ {-1, 1}, {n, 4}] (* _Michael De Vlieger_, Jul 22 2016 *)
%Y A137583 Cf. A093907, A137508, A138509, A137575.
%K A137583 nonn,less,fini,full
%O A137583 1,1
%A A137583 _Paul Curtz_, Apr 26 2008
%E A137583 Edited by _R. J. Mathar_, Oct 02 2009