OFFSET
1,2
FORMULA
a(n) = (A181162(n) - n^n)/2.
EXAMPLE
The a(2) = 3 pairs of maps [2] -> [2] are:
01: [ 1 1 ] [ 1 2 ]
02: [ 1 2 ] [ 2 1 ]
03: [ 1 2 ] [ 2 2 ]
CROSSREFS
KEYWORD
nonn
AUTHOR
Joerg Arndt, Feb 01 2015
STATUS
approved