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 A235937 #28 Jan 05 2019 01:32:45
%S A235937 0,0,0,0,1,2,11,62,408,3056,25821,242802,2517303,28540102,351383192,
%T A235937 4669815008,66640974977,1016522211474,16507095990251,284343231536742,
%U A235937 5178919228252440
%N A235937 Number of circular permutations with exactly one specified increasing or decreasing modular run (3-sequence), with clockwise and counterclockwise traversals not counted as distinct.
%C A235937 Arrangements that differ only in the direction in which the cycle is traversed do not count as different.
%C A235937 This sequence is the same as for straight permutations of {0,1,...,n} that begin with {0,1} and end with {n-1,n} but have no increasing or decreasing 3-sequence, viz., the sequence b(0,1...n-2,n-1) in Dymáček and Lambert.
%D A235937 Paul J. Campbell, Circular permutations with exactly one modular run (3-sequence), submitted to Journal of Integer Sequences
%H A235937 Wayne M. Dymáček and Isaac Lambert, <a href="http://www.cs.uwaterloo.ca/journals/JIS/VOL14/Dymacek/dymacek5.html">Circular permutations avoiding runs of i, i+1, i+2 or i, i-1, i-2</a>, Journal of Integer Sequences, Vol. 14 (2011) Article 11.1.6.
%e A235937 With specified sequence 123:
%e A235937 a(5) = 1: 12354.
%e A235937 a(6) = 2: 123564, 123645.
%e A235937 a(7) = 11: 1235476, 1235746, 1235764, 1236475, 1236574, 1236745, 1236754, 1237465, 1237546, 1237564, 1237645.
%Y A235937 Cf. A165961, A165964, A165962, A078628, A078673.
%Y A235937 Cf. A235938, A235939, A235940, A235941, A235942, A235943.
%K A235937 nonn
%O A235937 1,6
%A A235937 _Paul J. Campbell_, Jan 20 2014, with Joe Marasco and Ashish Vikram
%E A235937 a(20)-a(21) from _Alois P. Heinz_, Jan 24 2014
%E A235937 Obsolete b-file deleted by _N. J. A. Sloane_, Jan 05 2019