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 A137913 #8 Apr 18 2013 02:48:02 %S A137913 3,4,5,6,7,8,9,10,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35, %T A137913 36,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76, %U A137913 77,78,79,80,81,82,83,84,85,86 %N A137913 Rows 2, 4, 6 of Mendeleyev-Seaborg (extended to 32 columns) periodic table elements. %C A137913 58 terms. Companion of A137904(60 terms). Both "well" ordered give 118 terms sequence (increasing) 1 to 118;19-10=9, 55-36=19, a(n) differences lead to difference 3 before a(0)=3. Hence neutral element 0. %Y A137913 Cf. A134984, A135559. %K A137913 nonn,fini,full %O A137913 0,1 %A A137913 _Paul Curtz_, Apr 30 2008