OFFSET
0,3
LINKS
Alois P. Heinz, Table of n, a(n) for n = 0..1000
EXAMPLE
a(0) = 1: the empty word.
a(1) = 1: 0.
a(2) = 3: 00, 01, 11.
a(3) = 5: 000, 001, 010, 100, 101.
a(4) = 12: 0000, 0001, 0010, 0011, 0101, 0110, 0111, 1010, 1011, 1101, 1110, 1111.
CROSSREFS
KEYWORD
nonn
AUTHOR
Alois P. Heinz, Dec 18 2013
STATUS
approved