Binary Sieve of Primes
Geometric Patterns of the Prime numbers
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Geometric Patterns of the Prime numbers
Now that we know how to use arrays, we can find prime numbers using a much faster algorithm: the Sieve of Eratosthenes.
How to implement the Sieve of Eratosthenes automatically (follow up to Sieve I video). Excel Level: Intermediate (conditional formatting, AND/OR statements). Math Level: Elementary – College
Now that we know how to use arrays, we can use a much faster algorithm to find prime numbers: the sieve of Eratosthenes.
Sieve of Eratosthenes to find prime numbers. Also twin primes and sexy primes.
Shows how to find all the primes less than a given number and how to make transparencies that demonstrate the Sieve nicely. Excel Level: Beginning. Math Level: Elementary – College
The Ulam Spril was publicized by Stanislaw Ulam in 1963. The spiral can be generated using the sieve of Eratosthenes to etch out the prime numbers. This animation depicts 123 iterations of the sieve. Initially, the Ulam Spiral is drawn and the primes are colored dark red. Those primes that have a rank, the order that the prime appears in the prime number sequence, that is also prime are colored yellow, and those that have a rank that is a prime with a rank that is also prime are colored blue. The sieve begins with 2 and ‘evaporates’ every other cell. When a cell is evaporated, the cells ahead of it in the spiral shift back to fill the vacant space but they retain their original value for future division tests. The next iteration evaporates those cells divisible by 3, and then 5, 7 and so on. Red cells(primes) change to black when they are less than p^2. Thus, the area of the inner square is π(x)^2 (the prime counting function). What is left after all composites have been evaporated and the newly created black cells are interperted as composites is an exact replica of what we started with, only shifted in the hierarchy of primeness so to speak. The path of a couple of prime points is traced as they move to their final destination. Music by: cloudtalk, Austin Texas.
Finding all the prime numbers between 1 and 100 using the technique devised by the ancient Greek mathematician Eratosthenes