Search results
Results from the WOW.Com Content Network
In mathematics, the prime-counting function is the function counting the number of prime numbers less than or equal to some real number x. [1] [2] It is denoted by π(x) (unrelated to the number π). A symmetric variant seen sometimes is π 0 (x), which is equal to π(x) − 1 ⁄ 2 if x is exactly a prime number, and equal to π(x) otherwise.
Presumably from the practice, in counting sheep or large herds of cattle, of counting orally from one to twenty, and making a score or notch on a stick, before proceeding to count the next twenty. [3] [4] A distance of twenty yards in ancient archery and gunnery. [5] Threescore: 60 Three score (3x20) Large: 1,000 Slang for one thousand Myriad ...
In number theory, an n-smooth (or n-friable) number is an integer whose prime factors are all less than or equal to n. [ 1 ] [ 2 ] For example, a 7-smooth number is a number in which every prime factor is at most 7.
The first such distribution found is π(N) ~ N / log(N) , where π(N) is the prime-counting function (the number of primes less than or equal to N) and log(N) is the natural logarithm of N. This means that for large enough N, the probability that a random integer not greater than N is prime is very close to 1 / log(N).
where CF—the cumulative frequency—is the count of all scores less than or equal to the score of interest, F is the frequency for the score of interest, and N is the number of scores in the distribution. Alternatively, if CF ' is the count of all scores less than the score of interest, then
A prime number (or prime) is a natural number greater than 1 that has no positive divisors other than 1 and itself. ... (primes less than 2,000,000,000)
A number is positive if it is greater than zero. A number is negative if it is less than zero. A number is non-negative if it is greater than or equal to zero. A number is non-positive if it is less than or equal to zero. When 0 is said to be both positive and negative, [citation needed] modified phrases are used to refer to the sign of a number:
In mathematics, a set is countable if either it is finite or it can be made in one to one correspondence with the set of natural numbers. [a] Equivalently, a set is countable if there exists an injective function from it into the natural numbers; this means that each element in the set may be associated to a unique natural number, or that the elements of the set can be counted one at a time ...