# Greetings from The On-Line Encyclopedia of Integer Sequences! http://oeis.org/

Search: id:a165964
Showing 1-1 of 1

%I A165964 #9 Jul 22 2017 11:25:01
%S A165964 1,1,0,4,16,86,542,3932,32330,297438,3028320,33814454,410954878,
%T A165964 5400878692,76329470882,1154445436334,18606430004984,318369275913710,
%U A165964 5764046146341198,110091446931897180,2212282487296335866
%N A165964 Number of circular permutations of length n without increasing or decreasing 3-sequences.
%C A165964 Circular permutations are permutations whose indices are from the ring of integers modulo n. Increasing 3-sequences are of the form i,i+1,i+2, while decreasing 3-sequences are of the form i,i-1,i-2.
%H A165964 W. M. Dymacek, I. Lambert, <a href="https://cs.uwaterloo.ca/journals/JIS/VOL14/Dymacek/dymacek5.html">Permutations Avoiding Runs of i, i+1, i+2 or i, i-1, i-2 </a>, J. Int. Seq. 14 (2011) # 11.1.6, Table 1.
%F A165964 a(n) = A095816(n-1) - 2 * Sum{i=1,[n/3], A095816(n-3i) - A095816(n-1-3i)}.
%e A165964 For n=4 the a(4)=4 solutions are (0,1,3,2), (0,2,1,3), (0,2,3,1), and (0,3,1,2).
%Y A165964 Cf. A095816, A165963, A078628.
%K A165964 nonn
%O A165964 1,4
%A A165964 _Isaac Lambert_, Oct 07 2009
%E A165964 Edited and more terms added by _Max Alekseyev_, Jun 14 2011

# Content is available under The OEIS End-User License Agreement: http://oeis.org/LICENSE