OFFSET
0,3
EXAMPLE
a(3) = 12: (1,1,1), (1,1,3), (1,2,1), (1,2,2), (1,2,3), (1,3,3), (2,2,2), (2,2,3), (2,3,1), (3,1,2), (3,2,3), (3,3,3).
CROSSREFS
KEYWORD
nonn,more
AUTHOR
Alois P. Heinz, Sep 10 2014
EXTENSIONS
a(8)-a(10) from Bert Dobbelaere, Jan 24 2019
STATUS
approved