a(n) has n 1's followed by C(n-1,2) 0's.A127851a(n) has n 1's followed by C(n-1,2) 0's.Terms a(0) =0a(1) =1a(2) =11a(3) =1110a(4) =1111000a(5) =11111000000External referencesoeis: A127851