OFFSET
1,1
COMMENTS
a(6) from Gordon F. Royle.
LINKS
Swee Hong Chan and Igor Pak, Computational complexity of counting coincidences, arXiv:2308.10214 [math.CO], 2023. See p. 4.
EXAMPLE
a(2)=3 because {0,1,2} are expressible as permanents of (0, 1)-matrices.
CROSSREFS
KEYWORD
hard,more,nonn
AUTHOR
Hugo Pfoertner, Nov 05 2003
EXTENSIONS
a(7) from Giovanni Resta, Mar 29 2006
a(8) from Minfeng Wang, Oct 04 2024
STATUS
approved