de Bruijn Constant

The de Bruijn constant, also called the Copson-de Bruijn constant, is the minimal constant

(OEIS A113276) such that the inequality

always holds.

REFERENCES:

Copson, E. T. "Note on Series of Positive Terms." J. London Math. Soc. 2, 9-12, 1927.

Copson, E. T. "Note on Series of Positive Terms." J. London Math. Soc. 3, 49-51, 1928.

de Bruijn, N. G. Asymptotic Methods in Analysis. New York: Dover, 1981.

Finch, S. R. 'Copson-de Bruijn Constant." §3.5 in Mathematical Constants. Cambridge, England: Cambridge University Press, pp. 217-219, 2003.

Sloane, N. J. A. Sequence A113276 in "The On-Line Encyclopedia of Integer Sequences."