Approximating the number of integers without large prime factors

نویسنده

  • Koji Suzuki
چکیده

Ψ(x, y) denotes the number of positive integers ≤ x and free of prime factors > y. Hildebrand and Tenenbaum gave a smooth approximation formula for Ψ(x, y) in the range (log x)1+ < y ≤ x, where is a fixed positive number ≤ 1/2. In this paper, by modifying their approximation formula, we provide a fast algorithm to approximate Ψ(x, y). The computational complexity of this algorithm is O( √ (log x)(log y)). We give numerical results which show that this algorithm provides accurate estimates for Ψ(x, y) and is faster than conventional methods such as algorithms exploiting Dickman’s function.

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عنوان ژورنال:
  • Math. Comput.

دوره 75  شماره 

صفحات  -

تاریخ انتشار 2006