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 A241797 #6 Apr 28 2014 19:01:47 %S A241797 9,146,1324,8786,47013,214997,874413,3228005,11049817,35389760, %T A241797 107476721,310853113,863984856,2313084483,6003120701,15122836712, %U A241797 37154716734,89093938147,209258012995,481663102867,1089445474512,2422311605452,5305675093522,11451261202545 %N A241797 Number of ballot sequences of length n having exactly four descents. %e A241797 a(8) = 9: [1,2,1,2,1,3,2,1], [1,2,1,3,1,4,2,1], [1,2,1,3,2,1,2,1], [1,2,1,3,2,1,3,1], [1,2,1,3,2,1,3,2], [1,2,1,3,2,1,4,1], [1,2,1,3,2,1,4,2], [1,2,1,3,2,1,4,3], [1,2,1,3,2,4,3,1]. %Y A241797 Column k=4 of A238121 and of A238122. %K A241797 nonn %O A241797 8,1 %A A241797 _Joerg Arndt_ and _Alois P. Heinz_, Apr 28 2014