Let N = 123456789101112131415161718..., the concatenation of the natural numbers. a(n) is the n-digit number formed from the digits of N starting from the {n(n-1)/2 +1}th digit. Omit any leading zeros.

A066547

Let N = 123456789101112131415161718..., the concatenation of the natural numbers. a(n) is the n-digit number formed from the digits of N starting from the {n(n-1)/2 +1}th digit. Omit any leading zeros.