A127851 a(n) has n 1's followed by C(n-1,2) 0's.

0, 1, 11, 1110, 1111000, 11111000000, 1111110000000000, 1111111000000000000000, 11111111000000000000000000000, 1111111110000000000000000000000000000

Offset: 0

Author

Paul Barry, Feb 02 2007

Keywords

• easy
• nonn

Comments

Base 2 version of A127850.

Formula

a(n)=10^C(n,2)*(10^n-1)/(9*10^(n-1))