OFFSET
0,4
COMMENTS
Sizes of orbits are given by A000793.
LINKS
Alois P. Heinz, Table of n, a(n) for n = 0..130
FORMULA
EXAMPLE
For S={a}, n=1 and only one operation possible {a->a}. For S={a,b}, n=2 and possible operations are {a->a,b->a}, {a->a,b->b}, {a->b,b->a},{a->b,b->b}. Longest orbit generated by applying operation {a->b,b->a}: initial set (a,b), applying function gives orbit - (b,a), (a,b). All other possible functions are generating fixed points.
CROSSREFS
KEYWORD
nonn
AUTHOR
Dmitriy Samsonov (dmitriy.samsonov(AT)gmail.com), Jul 10 2009
EXTENSIONS
a(0), a(10)-a(23) from Alois P. Heinz, Jul 12 2017
a(21)-a(22) corrected by Alois P. Heinz, Aug 16 2017
STATUS
approved