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 A217923 #33 Jun 16 2022 01:52:40 %S A217923 57,58,59,60,61,62,63,64,65,66,67,68,69,70,89,90,91,92,93,94,95,96,97, %T A217923 98,99,100,101,102 %N A217923 F-block elements for Janet periodic table. %C A217923 From _Paul Curtz_, Oct 26 2012: (Start) %C A217923 Tarantola's formulas for the Janet table: %C A217923 Let D(n) = n*(n+1)*(n+2)/6 + (1-(-1)^n)*(n+1)/4 = A168380(n). %C A217923 The row R at which the element with atomic number Z is to be placed is the unique value of R satisfying D(R-1) < Z <= D(R). %C A217923 Once the row number R is determined, the column number is, from right to left, C = D(R) - Z + 1. %C A217923 Example: Z=109. D(7) < Z <= D(8) = 120. C = 120 - 109 + 1 = 12. (End) %H A217923 Wikipedia, <a href="http://en.wikipedia.org/wiki/Charles_Janet">The Janet periodic table</a> %t A217923 Join[Range[57,70], Range[89,102]] %Y A217923 Cf. A160914 (s-block), A138469 (p-block), A199934 (d-block). %K A217923 nonn,tabf,fini %O A217923 1,1 %A A217923 _Jean-François Alcover_, Oct 15 2012