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Feller–Tornier constant

In mathematics, the Feller–Tornier constant CFT is the density of the set of all integers that have an even number of prime factors (counted by multiplicities).[1] It is named after William Feller (1906–1970) and Erhard Tornier (1894–1982)[2]

(sequence A065493 in the OEIS)

Omega functionEdit

The Omega function is given by


The Iverson bracket is


With these notations, we have


Prime zeta functionEdit

The prime zeta function P is give by


The Feller–Tornier constant satisfies


See alsoEdit


  1. ^ "Feller–Tornier Constant – from Wolfram MathWorld". 2017-03-23. Retrieved 2017-03-30.
  2. ^ Steven R. Finch. "Mathematical Constants. (Cf. Feller–Tornier constant.)". Retrieved 2017-03-30.