OFFSET
0,3
LINKS
Alois P. Heinz, Table of n, a(n) for n = 0..180
FORMULA
a(n) ~ n^n. - Vaclav Kotesovec, Aug 29 2014
EXAMPLE
a(1) = 1: [1].
a(2) = 2: [1,2], [2,1].
a(3) = 24: [1,1,2], [1,1,3], [1,2,1], [1,2,2], [1,2,3], [1,3,1], [1,3,2], [1,3,3], [2,1,1], [2,1,2], [2,1,3], [2,2,1], [2,2,3], [2,3,1], [2,3,2], [2,3,3], [3,1,1], [3,1,2], [3,1,3], [3,2,1], [3,2,2], [3,2,3], [3,3,1], [3,3,2].
CROSSREFS
KEYWORD
nonn
AUTHOR
Alois P. Heinz, Aug 27 2013
STATUS
approved