OFFSET
0,2
COMMENTS
Number of digits of a(n) is A001405(n).
a(2n) begins with exactly A000108(n) 1's. - Vladimir Shevelev, Feb 07 2014
LINKS
Alois P. Heinz, Table of n, a(n) for n = 0..12
EXAMPLE
Triangle begins
. 1
.
. 1 1
.
. 1 11 1
.
. 1 111 111 1
.
. 1 1111 111111 1111 1
MAPLE
a:= n-> add((10^binomial(n, k)-1)/9, k=0..n):
seq(a(n), n=0..8); # Alois P. Heinz, Feb 01 2014
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Vladimir Shevelev, Feb 01 2014
STATUS
approved