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 A376694 #9 Oct 02 2024 07:55:09 %S A376694 1,1,2,6,22,100,548,3482,25256,206298,1871704,18676354,203323724, %T A376694 2397969518,30455963576,414446765490,6015821216380,92778775395190, %U A376694 1515047281161392,26114701159308242,473827422862284740,9027024454944900390,180165845677134636856,3759286756628732868754,81850596163629861103004 %N A376694 Number of permutations of order n avoiding consecutive pattern 121'3. %C A376694 To avoid 121'3 means not to have four consecutive letters such that the first letter and the third one is less than the second, and the second one is less than and the fourth one. %H A376694 S. Kitaev, <a href="https://doi.org/10.1016/j.dam.2006.09.011">Introduction to partially ordered patterns</a>, Discrete Applied Mathematics 155 (2007), 929-944. [WARNING: The sequence is erroneously given as 1, 2, 6, 20, 83, 411, ...] %Y A376694 Cf. A117156, A177470, A177471, A177472, A177473, A177475, A177476, A177477, A177478, A177479, A177480, A177481, A177482, A177483, A177484. %K A376694 nonn %O A376694 0,3 %A A376694 _Max Alekseyev_, Oct 01 2024