Feeds
已解决
Sum of big primes without primes
Inspired by Project Euler n°10 (I am quite obviously a fan). With problem n°250 by Doug, you can find some global methods to co...
7 months 前
已解决
Sums of cubes and squares of sums
Given the positive integers 1:n, can you: 1. Compute twice the sum of the cubes of those numbers. 2. Subtract the square...
7 months 前
已解决
Project Euler: Problem 6, Natural numbers, squares and sums.
The sum of the squares of the first ten natural numbers is, 1^2 + 2^2 + ... + 10^2 = 385 The square of the sum of the first ...
7 months 前
已解决
Identify Wagstaff primes
The numbers 3, 43, and 2731 are examples of <https://mathworld.wolfram.com/WagstaffPrime.html Wagstaff primes>. Write a func...
7 months 前
已解决
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:/...
7 months 前
已解决
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...
7 months 前
已解决
Find the last non-zero digit in a primorial
<https://www.mathworks.com/matlabcentral/cody/groups/2001/problems/45251 Cody Problem 45251> asked us to find the last non-zero ...
7 months 前
已解决
Identify primorial primes
Cody Problems <https://www.mathworks.com/matlabcentral/cody/problems/46054-count-trailing-zeros-in-a-primorial 46054> and <https...
7 months 前
已解决
Count trailing zeros in a primorial
<https://www.mathworks.com/matlabcentral/cody/problems/44068-the-number-of-trailing-zero-digit-of-a-factorial Cody Problem 44068...
7 months 前
已解决
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...
7 months 前
已解决
List the emirps
An emirp is a prime number that becomes a different prime when reversed. The numbers 13, 17, and 149 are emirps, but 11, 19, and...
7 months 前
已解决
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...
7 months 前
已解决
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...
7 months 前
已解决
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)...
7 months 前
已解决
Sum all integers from 1 to 2^n
Given the number x, y must be the summation of all integers from 1 to 2^x. For instance if x=2 then y must be 1+2+3+4=10.
7 months 前
已解决
Magic is simple (for beginners)
Determine for a magic square of order n, the magic sum m. For example m=15 for a magic square of order 3.
7 months 前
已解决
Make a random, non-repeating vector.
This is a basic MATLAB operation. It is for instructional purposes. --- If you want to get a random permutation of integer...
7 months 前
已解决
Number of 1s in a binary string
Find the number of 1s in the given binary string. Example. If the input string is '1100101', the output is 4. If the input stri...
7 months 前
已解决
Pi Estimate 1
Estimate Pi as described in the following link: <http://www.people.virginia.edu/~teh1m/cody/Pi_estimation1.pdf>
7 months 前
已解决
Return the first and last characters of a character array
Return the first and last character of a string, concatenated together. If there is only one character in the string, the functi...
7 months 前
已解决
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]; ...
7 months 前
已解决
Create times-tables
At one time or another, we all had to memorize boring times tables. 5 times 5 is 25. 5 times 6 is 30. 12 times 12 is way more th...
7 months 前
已解决
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...
7 months 前
已解决
Getting the indices from a vector
This is a basic MATLAB operation. It is for instructional purposes. --- You may already know how to find the logical indices o...
7 months 前
已解决
Swap the first and last columns
Flip the outermost columns of matrix A, so that the first column becomes the last and the last column becomes the first. All oth...
7 months 前
已解决
Triangle Numbers
Triangle numbers are the sums of successive integers. So 6 is a triangle number because 6 = 1 + 2 + 3 which can be displayed ...
7 months 前
已解决
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...
7 months 前
已解决
Generate a vector like 1,2,2,3,3,3,4,4,4,4
Generate a vector like 1,2,2,3,3,3,4,4,4,4 So if n = 3, then return [1 2 2 3 3 3] And if n = 5, then return [1 2 2 3 3 3 4...
7 months 前
已解决
Largest Twin Primes
<http://en.wikipedia.org/wiki/Twin_prime Twin primes> are primes p1, p2 = p1 + 2 such that both p1 and p2 are prime numbers. Giv...
7 months 前
