OFFSET
1,2
EXAMPLE
Using double factorials (!!) augments A064818 for example by 3 = 3!! and by 15 = (5!!)*1 = (5!!)/1 = (5!!)^1.
CROSSREFS
KEYWORD
more,nonn
AUTHOR
Paolo P. Lava & Giorgio Balzarotti, Jul 16 2009
EXTENSIONS
Definition rephrased by R. J. Mathar, Aug 27 2009
STATUS
approved