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 A158431 #4 Feb 16 2025 08:33:09
%S A158431 1,26,458,6995,101027,1436898,20572392,300418660,4513021536,
%T A158431 70158846231,1133525183816,19092510077724
%N A158431 Number of permutations of 1..n containing the relative rank sequence { 45231 } at any spacing.
%C A158431 Same series for 53421 13245 12435 54231 21435 13254 53412
%H A158431 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/PermutationPattern.html">Permutation Pattern</a>
%Y A158431 A056986 A158005
%K A158431 nonn
%O A158431 5,2
%A A158431 _R. H. Hardin_ Mar 18 2009