login
A282847
Given n people seated at a table, a(n) is the minimum number of swaps that must occur in order for everybody to have sat next to every other person.
0
0, 0, 0, 1, 3, 4, 4, 6, 8, 10, 12, 14, 17, 20
OFFSET
1,5
COMMENTS
a(n) >= ceiling(n(n-3)/8).
EXAMPLE
For n = 7 the a(7) = 4 swaps are:
(1) 1 swaps with 4,
(2) 1 swaps with 5,
(3) 3 swaps with 6, and then
(4) 2 swaps with 6.
CROSSREFS
Sequence in context: A363527 A224212 A078490 * A363239 A047877 A351371
KEYWORD
nonn,hard,more
AUTHOR
Peter Kagey, Feb 24 2017
EXTENSIONS
a(13) and a(14) added by Dmitry Kamenetsky, Feb 26 2017
STATUS
approved