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 A158423 #16 Feb 16 2025 08:33:09
%S A158423 1,26,459,7034,101953,1454402,20863742,304906732,4578822750,
%T A158423 71092815624,1146499731400,19270199314388,338394827020511,
%U A158423 6218127006568582,119650035623211443,2410982527835022898,50846926185692443237,1121251553648267523078,25820703260713964268656,620088145746453017943268
%N A158423 Number of permutations of 1..n containing the relative rank sequence { 23145 } at any spacing.
%C A158423 Same series for 43521 12534 54132 35421 31245 12453 54213 43512 23154 21534 45132 35412 31254 21453 45213.
%H A158423 Martin Fuller, <a href="/A158423/b158423.txt">Table of n, a(n) for n = 5..38</a>
%H A158423 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/PermutationPattern.html">Permutation Pattern</a>
%F A158423 Conjecture: a(n) + A116485(n) = n!. - _Benedict W. J. Irwin_, Mar 15 2016
%F A158423 Proof: see A116485.
%Y A158423 Cf. A056986, A158005, A116485.
%K A158423 nonn
%O A158423 5,2
%A A158423 _R. H. Hardin_, Mar 18 2009
%E A158423 a(17) onwards from A116485, by _Martin Fuller_, Aug 26 2023