Duong

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Find the sum of all the numbers of the input vector
Find the sum of all the numbers of the input vector x. Examples: Input x = [1 2 3 5] Output y is 11 Input x ...

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Sophie Germain prime
In number theory, a prime number p is a *Sophie Germain prime* if 2p + 1 is also prime. For example, 23 is a Sophie Germain prim...

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Find nearest prime number less than input number
Find nearest prime number less than input number. For example: if the input number is 125, then the nearest prime number whi...

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Mersenne Primes
A Mersenne prime is a prime number of the form M = 2^p - 1, where p is another prime number. For example, 31 is a Mersenne prim...

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Make a vector of prime numbers
Input(n) - length of vector with prime numbers Output(v) - vector of prime numbers Example: * n=1; v=2 * n=3; v=[2 3 5...

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Find the next prime number
Find the next prime number or numbers for given n. For example: n = 1; out = 2; or n = [5 7]; out = [7 11]; ...

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Factorize THIS, buddy
List the prime factors for the input number, in decreasing order. List each factor only once, even if the factorization includes...

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Generalised Hamming Number
Inspired by Project Euler n°204 and Problem 1308 by James A generalised Hamming number of type n, has no prime factor larger ...

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Numbers with prime factors 2, 3 and 5.
Make a function which takes one positive integer n and returns a matrix with the numbers of the form (2^i)*(3^j)*(5^k) which are...

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Proper Factors
Generate the proper factors of input integer x and return them in ascending order. For more information on proper factors, refer...

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Multiples of a Number in a Given Range
Given an integer factor _f_ and a range defined by _xlow_ and _xhigh_ inclusive, return a vector of the multiples of _f_ that fa...

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Smith numbers
Return true if the input is a Smith number in base ten. Otherwise, return false. Read about Smith numbers at http://en.wikipedia...

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Prime factor digits
Consider the following number system. Calculate the prime factorization for each number n, then represent the prime factors in a...

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Approximation of Pi
Pi (divided by 4) can be approximated by the following infinite series: pi/4 = 1 - 1/3 + 1/5 - 1/7 + ... For a given number of...

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radius of a spherical planet
You just measured its surface area, that is the input.

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Project Euler: Problem 10, Sum of Primes
The sum of the primes below 10 is 2 + 3 + 5 + 7 = 17. Find the sum of all the primes below the input, N. Thank you <http:/...

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Project Euler: Problem 9, Pythagorean numbers
A Pythagorean triplet is a set of three natural numbers, a b c, for which, a^2 + b^2 = c^2 For example, 3^2 + 4^2 = 9 + 16 ...

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Project Euler: Problem 8, Find largest product in a large string of numbers
Find the greatest product of five consecutive digits in an n-digit number. 73167176531330624919225119674426574742355349194934...

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Project Euler: Problem 5, Smallest multiple
2520 is the smallest number that can be divided by each of the numbers from 1 to 10 without any remainder. What is the smalle...

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Project Euler: Problem 4, Palindromic numbers
A palindromic number reads the same both ways. The largest palindrome made from the product of two 2-digit numbers is 9009 = 91 ...

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Project Euler: Problem 3, Largest prime factor
The prime factors of 13195 are 5, 7, 13 and 29. What is the largest prime factor of the number being input, input might be ui...

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Project Euler: Problem 1, Multiples of 3 and 5
If we list all the natural numbers below 10 that are multiples of 3 or 5, we get 3, 5, 6 and 9. The sum of these multiples is 23...

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Is X a Fibonacci Matrix?
In honor of Cleve's new blog and post: <http://blogs.mathworks.com/cleve/2012/06/03/fibonacci-matrices/> Is X a Fibonacci ...

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Fibonacci Decomposition
Every positive integer has a unique decomposition into nonconsecutive Fibonacci numbers f1+f2+ ... Given a positive integer n, r...

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How many Fibonacci numbers?
Find the number of unique Fibonacci numbers (don't count repeats) in a vector of positive integers. Example: x = [1 2 3 4...

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Triangle sequence
A sequence of triangles is constructed in the following way: 1) the first triangle is Pythagoras' 3-4-5 triangle 2) the second...

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Number of Even Elements in Fibonacci Sequence
Find how many even Fibonacci numbers are available in the first d numbers. Consider the following first 14 numbers 1 1 2...

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Fibonacci-Sum of Squares
Given the Fibonacci sequence defined by the following recursive relation, * F(n) = F(n-1) + F(n-2) * where F(1) = 1 and F(1)...

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Right and wrong
Given a vector of lengths [a b c], determines whether a triangle with those sides lengths is a right triangle: <http://en.wikipe...

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Great Circle Distance
Find shortest between two points on a ball given their azimuthal and polar angles (in degrees) as well as the radius of the sphe...

1 year ago