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 A151578 #8 May 06 2020 01:37:41
%S A151578 0,6,399,9528,140571,1561900,14413894,116857368,862140162,5925941490,
%T A151578 38576132625,240659672336,1451515055333,8520359419080,48925419854400,
%U A151578 275923203690000,1533178869210324,8414851432723230,45712442315346915,246193095207323400,1316311515774609375
%N A151578 Number of permutations of 1..n arranged in a circle with exactly 5 adjacent element pairs in decreasing order.
%H A151578 Andrew Howroyd, <a href="/A151578/b151578.txt">Table of n, a(n) for n = 5..500</a>
%F A151578 From _Andrew Howroyd_, May 05 2020: (Start)
%F A151578 a(n) = n*A000505(n-1).
%F A151578 a(n) = n*(5^(n-1) - n*4^(n-1) + binomial(n,2)*3^(n-1) - binomial(n,3)*2^(n-1) + binomial(n,4)). (End)
%o A151578 (PARI) a(n) = {n*(5^(n-1) - n*4^(n-1) + binomial(n,2)*3^(n-1) - binomial(n,3)*2^(n-1) + binomial(n,4))} \\ _Andrew Howroyd_, May 05 2020
%Y A151578 Column k=5 of A334218.
%Y A151578 Cf. A000505.
%K A151578 nonn
%O A151578 5,2
%A A151578 _R. H. Hardin_, May 21 2009
%E A151578 Terms a(17) and beyond from _Andrew Howroyd_, May 05 2020