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 A294847 #19 Dec 31 2020 11:11:15 %S A294847 2,4,6,8,12,14,20,22,28,32,38,40,48,50,56,64,74,76,86,88,98,106,112, %T A294847 114,126,132,138,146,160,162 %N A294847 a(n) is the total number of line segments in the diagram described in A236104 after n-th stage, with a(0) = 2. %C A294847 Note that the diagram is also the top view of the stepped pyramid with n levels described in A245092. %C A294847 For the construction of the diagram using Dyck paths and for more information about the pyramid see A237593. %e A294847 Illustration of initial terms (n = 1..6): %e A294847 . _ _ _ _ %e A294847 . _ _ _ |_ _ _ |_ %e A294847 . _ _ _ |_ _ _| |_ _ _| |_ %e A294847 . _ _ |_ _ |_ |_ _ |_ _ |_ _ |_ _ | %e A294847 . _ _ |_ _|_ |_ _|_ | |_ _|_ | | |_ _|_ | | | %e A294847 . _ |_ | |_ | | |_ | | | |_ | | | | |_ | | | | | %e A294847 . |_| |_|_| |_|_|_| |_|_|_|_| |_|_|_|_|_| |_|_|_|_|_|_| %e A294847 . %e A294847 . 4 6 8 12 14 20 %Y A294847 Cf. A000203, A024916, A196020, A235791, A236104, A237048, A237270, A237271, A237590, A237591, A237593, A245092, A262626, A294723. %K A294847 nonn,more %O A294847 0,1 %A A294847 _Omar E. Pol_, Nov 09 2017