OFFSET
2,2
LINKS
P. J. Cameron, M. Gadouleau, J. D. Mitchell, and Y. Peresse, Chains of subsemigroups, arXiv preprint arXiv:1501.06394 [math.GR], 2015. See Table 1.
CROSSREFS
KEYWORD
nonn,more
AUTHOR
N. J. A. Sloane, Sep 21 2015
EXTENSIONS
Missing term a(3) added by Pontus von Brömssen, Jul 08 2024
STATUS
approved