OFFSET
4,1
REFERENCES
J. P. Hayes, Enumeration of fanout-free Boolean functions, J. ACM, 23 (1976), 700-709.
FORMULA
~Hayes (1976, Theorem 3) gives a recurrence.
CROSSREFS
KEYWORD
nonn,more
AUTHOR
N. J. A. Sloane, Apr 30 2013
STATUS
approved