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 A322251 #6 Dec 02 2018 08:51:48 %S A322251 1,1,1,2,8,32,132,702,4566,31670,237446,2010626,18782106,187594266, %T A322251 2009039346,23200862726,286250968646,3740867774726,51734894498790, %U A322251 756345994706634,11641318110171330,188004200777993570,3180713596572408650,56276908859288339822 %N A322251 Number of permutations of [n] in which the length of every increasing run is 0 or 1 (mod 3). %H A322251 Alois P. Heinz, <a href="/A322251/b322251.txt">Table of n, a(n) for n = 0..470</a> %Y A322251 Cf. A317111, A322262. %K A322251 nonn %O A322251 0,4 %A A322251 _Alois P. Heinz_, Nov 30 2018