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 A174028 #9 Jan 22 2014 17:58:32 %S A174028 2,2,6,2,6,10,2,6,10,14,2,6,10,14,18,2,6,10,14,18,22,2,6,10,14,18,22, %T A174028 26,2,6,10,14,18,22,26,30,2,6,10,14,18,22,26,30,34,2,6,10,14,18,22,26, %U A174028 30,34,38 %N A174028 Triangle T(n,k) = 2+4k read by rows. %H A174028 Wikipedia, <a href="http://en.wikipedia.org/wiki/Electron_shell">Electron shell</a> %F A174028 T(n,k) = A016825(k). %F A174028 T(n,k) = 2*A158405(n+1,k). %e A174028 2; %e A174028 2, 6; %e A174028 2, 6, 10; %e A174028 2, 6, 10, 14; %e A174028 2, 6, 10, 14, 18; %e A174028 2, 6, 10, 14, 18, 22; %e A174028 2, 6, 10, 14, 18, 22, 26; %Y A174028 Cf. A001105 (row sums), A167268. %K A174028 nonn,easy,tabl %O A174028 0,1 %A A174028 _Paul Curtz_, Mar 06 2010