Note on Normal Decimals
H. Davenport, Paul L. Erdos · Canadian Journal of Mathematics · 1952
A real number, expressed as a decimal, is said to be normal (in the scale of 10) if every combination of digits occurs in the decimal with the proper frequency. If a 1 a 2 … a k is any combination of k digits, and N ( t ) is the number of times this combination occurs among the first t digits, the condition is that 1