OFFSET
4,3
EXAMPLE
a(5) = 1: 11111.
a(6) = 3: 11121, 11211, 12111.
a(7) = 9: 11131, 11221, 11311, 12121, 12211, 13111, 21112, 111112, 211111.
a(8) = 21: 11141, 11231, 11321, 11411, 12131, 12221, 12311, 13121, 13211, 14111, 21122, 21212, 22112, 111113, 111212, 112112, 121112, 211121, 211211, 212111, 311111.
CROSSREFS
KEYWORD
nonn
AUTHOR
Alois P. Heinz, Sep 14 2015
STATUS
approved