The Copeland-Erdős constant is the constant with decimal expansion 0.23571113171923... (OEIS A033308) obtained by concatenating consecutive
primes: 2, 23, 235, 2357, 235711, ... (OEIS A019518).
It is one of the Smarandache sequences and
is considered as an infinite word by Allouche and Shallit (2003, pp. 299 and
334).
It is therefore given by the formula
Copeland and Erdős (1946) showed that it is a normal
number in base 10.
Allouche, J.-P. and Shallit, J. Automatic Sequences: Theory, Applications, Generalizations. Cambridge, England: Cambridge
University Press, 2003.Bailey, D. H. and Crandall, R. E. "Random
Generators and Normal Numbers." Exper. Math.11, 527-546, 2002.Champernowne,
D. G. "The Construction of Decimals Normal in the Scale of Ten." J.
London Math. Soc.8, 1933.Copeland, A. H. and Erdős,
P. "Note on Normal Numbers." Bull. Amer. Math. Soc.52, 857-860,
1946.Pickover, C. A. The
Mathematics of Oz: Mental Gymnastics from Beyond the Edge. New York: Cambridge
University Press, p. 284, 2002.Sloane, N. J. A. Sequences
A019518, A030168,
A033308, A033309,
A033310, and A224890
in "The On-Line Encyclopedia of Integer Sequences."