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Sieve of Eratosthenes: algorithm steps for primes below 121 (including optimization of starting from prime's square). In mathematics, the sieve of Eratosthenes is an ancient algorithm for finding all prime numbers up to any given limit.
The prototypical example of a sifted set is the set of prime numbers up to some prescribed limit X. Correspondingly, the prototypical example of a sieve is the sieve of Eratosthenes, or the more general Legendre sieve. The direct attack on prime numbers using these methods soon reaches apparently insuperable obstacles, in the way of the ...
A prime sieve or prime number sieve is a fast type of algorithm for finding primes. There are many prime sieves. The simple sieve of Eratosthenes (250s BCE), the sieve of Sundaram (1934), the still faster but more complicated sieve of Atkin [1] (2003), sieve of Pritchard (1979), and various wheel sieves [2] are most common.
In this example the fact that the Legendre identity is derived from the Sieve of Eratosthenes is clear: the first term is the number of integers below X, the second term removes the multiples of all primes, the third term adds back the multiples of two primes (which were miscounted by being "crossed out twice") but also adds back the multiples ...
Sieve method, or the method of sieves, can mean: in mathematics and computer science, the sieve of Eratosthenes, a simple method for finding prime numbers in number theory, any of a variety of methods studied in sieve theory; in combinatorics, the set of methods dealt with in sieve theory or more specifically, the inclusion–exclusion principle
The principle can be viewed as an example of the sieve method extensively used in number theory and is sometimes referred to as the sieve formula. [ 4 ] As finite probabilities are computed as counts relative to the cardinality of the probability space , the formulas for the principle of inclusion–exclusion remain valid when the cardinalities ...
REM Eratosthenes Sieve Prime Number Program in BASIC 1 SIZE = 8190 2 DIM FLAGS (8191) 3 PRINT "Only 1 iteration" 5 COUNT = 0 6 FOR I = 0 TO SIZE 7 FLAGS (I) = 1 8 NEXT I 9 FOR I = 0 TO SIZE 10 IF FLAGS (I) = 0 THEN 18 11 PRIME = I + I + 3 12 K = I + PRIME 13 IF K > SIZE THEN 17 14 FLAGS (K) = 0 15 K = K + PRIME 16 GOTO 13 17 COUNT = COUNT + 1 ...
Just use three colours, one for the number used is the current step of the sieve, one for non-primes and then one for primes. And highlight clearly you start fron n 2 when using n in the sieve by making the number flash or something. C e n t y 22:02, 28 September 2007 (UTC) Oppose per centy.