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 A189077 #12 Apr 01 2020 12:11:51 %S A189077 1,1,2,4,8,16,31,60,115,218,411,770,1434,2656,4897,8991 %N A189077 Number of compositions of n that avoid the pattern 13-2. %H A189077 S. Heubach, T. Mansour and A. O. Munagi, <a href="https://web.math.rochester.edu/misc/ojac/vol4/CompType21.pdf">Avoiding Permutation Patterns of Type (2,1) in Compositions</a>, Online Journal of Analytic Combinatorics, 4 (2009). %Y A189077 Cf. A189075, A189076. %K A189077 nonn,more %O A189077 0,3 %A A189077 _N. J. A. Sloane_, Apr 16 2011