OFFSET
0,3
FORMULA
a(n) = 2*floor(n/2)*(n-2)!/floor(n/2)!^2 for n>=2.
a(n+2) = 2*A057977(n) for n>=0. - Peter Luschny, Jul 17 2016
MAPLE
CROSSREFS
KEYWORD
nonn
AUTHOR
Peter Luschny, Apr 25 2014
STATUS
approved