

A242523


Number of cyclic arrangements of S={1,2,...,n} such that the difference between any two neighbors is at least 3.


16



0, 0, 0, 0, 0, 0, 1, 11, 125, 1351, 15330, 184846, 2382084, 32795170, 481379278, 7513591430, 124363961357, 2176990766569, 40199252548280, 781143277669538, 15937382209774353, 340696424417421213, 7616192835573406931, 177723017354688250713, 4321711817908214684734
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OFFSET

1,8


COMMENTS

a(n)=NPC(n;S;P) is the count of all neighborproperty cycles for a specific set S of n elements and a specific pairproperty P. For more details, see the link and A242519.


LINKS

Hiroaki Yamanouchi, Table of n, a(n) for n = 1..27 (terms a(1)a(15) from Stanislav Sykora)
S. Sykora, On NeighborProperty Cycles, Stan's Library, Volume V, 2014.


EXAMPLE

The shortest cycle with this property has length n=7: {1,4,7,3,6,2,5}.


PROG

(C++) See the link.


CROSSREFS

Cf. A242519, A242520, A242521, A242522, A242524, A242525, A242526, A242527, A242528, A242529, A242530, A242531, A242532, A242533, A242534.
Sequence in context: A015594 A209605 A282755 * A015596 A163310 A240335
Adjacent sequences: A242520 A242521 A242522 * A242524 A242525 A242526


KEYWORD

nonn,hard


AUTHOR

Stanislav Sykora, May 27 2014


EXTENSIONS

a(16)a(25) from Hiroaki Yamanouchi, Aug 28 2014


STATUS

approved



