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 A262128 #5 Sep 11 2015 19:19:22 %S A262128 1,1,1,3,9,44,219,1445,9985,82741,728311,7283418,77655753,911793737, %T A262128 11395412415,153867507695,2202984651649,33654697818232, %U A262128 542738828304115,9258768392128641,166006249865713377,3128678609433086381,61725044306956275015,1273822982167765885166 %N A262128 Number of permutations p of [n] such that the up-down signature of p has nonnegative partial sums with a maximal value <= 3. %H A262128 Alois P. Heinz, <a href="/A262128/b262128.txt">Table of n, a(n) for n = 0..450</a> %F A262128 a(n) = A262124(n,3). %Y A262128 Column k=3 of A262124. %K A262128 nonn %O A262128 0,4 %A A262128 _Alois P. Heinz_, Sep 11 2015