Problem 52784. Easy Sequences 38: Prime Number Delta
where
is the prime counting function (number of prime numbers
), and
is the natural logarithm of x. The convergence of the abovementioned limit, first conjectured by Legendre in 1798, is now well established.
In this exercise we are more concerned with the difference function Δ, defined as follows:
where the symbol
means rounding-off to nearest integer. Δ appears divergent and seems to increase without bound as x increases.
Given a number d, our goal is to find the value of integer x when
first exceeds d.
As an example, if
, the value of x is
since:
and for all
,
.
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Easy Sequences Volume VI
- 10 Problems
- 2 Finishers
- Easy Sequences 38: Prime Number Delta
- Easy Sequences 39: Perfect Squares in Pascal's Triangle
- Easy Sequences 41: Boxes with Integer Edges
- Easy Sequences 42: Areas of Non-constructible Polygons
- Easy Sequences 44: Finding the Smallest Number whose Cube is divisible by a Factorial
- Easy Sequences 45: Second Derivative of Inverse Polynomial Function
- Easy Sequences 46: Semi-prime Leap Year Pairs
- Easy Sequences 47: Boxes with Prime Edges
- Easy Sequences 48: Prime Big Omega of Factorial Sequence
- Easy Sequences 49: Prime Little Omega Function
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