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 A151580 #7 May 06 2020 01:37:52 %S A151580 0,8,2223,146080,5007112,116857368,2112659718,31852408056, %T A151580 419567641380,4982201574576,54527214028669,559001753070984, %U A151580 5433944411838700,50558500037520720,453570522365097900,3946487691743226960,33461385366044612088,277535329177185004536 %N A151580 Number of permutations of 1..n arranged in a circle with exactly 7 adjacent element pairs in decreasing order. %H A151580 Andrew Howroyd, <a href="/A151580/b151580.txt">Table of n, a(n) for n = 7..500</a> %F A151580 a(n) = n*A001243(n-1). - _Andrew Howroyd_, May 05 2020 %Y A151580 Column k=7 of A334218. %Y A151580 Cf. A001243. %K A151580 nonn %O A151580 7,2 %A A151580 _R. H. Hardin_, May 21 2009 %E A151580 Terms a(16) and beyond from _Andrew Howroyd_, May 05 2020