OFFSET
1,2
COMMENTS
The number of closed binary operations F on a set of order n such that {F} is functionally complete.
a(3) computed by Craig Gidney, corrected by Code Golf Stack Exchange user AnttiP.
a(4) computed by Code Golf Stack Exchange user AnttiP.
a(5) computed by Code Golf Stack Exchange user gsitcia.
LINKS
R. O. Davies, On n-Valued Sheffer Functions, Mathematical Logic Quarterly, 25 (1979), 293-298.
Craig Gidney, Exploring Universal Ternary Gates.
Woosuk Kwak, Counting universal n-ary logic gates, Code Golf Stack Exchange.
Wikipedia, Logic gate.
Wikipedia, Functional completeness.
FORMULA
Limit_{n->oo} a(n)/A002489(n) = 1/e.
EXAMPLE
For n = 2, the two universal logic gates are NAND and NOR.
CROSSREFS
KEYWORD
nonn,hard,more
AUTHOR
Woosuk Kwak, Dec 29 2021
EXTENSIONS
a(5) added by Woosuk Kwak, Nov 23 2023
STATUS
approved