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 A158009 #7 Feb 16 2025 08:33:09
%S A158009 1,17,207,2278,24527,268104,3036850,36092688,453570148,6053567742,
%T A158009 85968651558,1299069917989
%N A158009 Numbers of pattern-matching permutations of (1324) for the permutations of {1, 2, ..., n} on n = 4, 5, 6, ... elements.
%C A158009 Same series for 4231. - _R. H. Hardin_, Mar 15 2009
%H A158009 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/PermutationPattern.html">Permutation Pattern</a>
%K A158009 nonn,more
%O A158009 4,2
%A A158009 _Eric W. Weisstein_, Mar 11 2009
%E A158009 More terms from _R. H. Hardin_, Mar 15 2009