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Matrix with different incremental runs
Given a vector of positive integers a = [ 3 2 4 ]; create the matrix where the *i* th column contains the vector *1:a(i)...

6 years ago

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Flip the main diagonal of a matrix
Given a n x n matrix, M, flip its main diagonal. Example: >> M=magic(5); >> flipDiagonal(M) 9 24 1 ...

6 years ago

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Back to basics 23 - Triangular matrix
Covering some basic topics I haven't seen elsewhere on Cody. Given an input matrix, return a matrix with all elements above a...

6 years ago

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Compute Fibonacci Number
Compute the _n_-th Fibonacci Number f(0) = 0, f(1) = 1, f(2) = 1, f(3) = 2, ... f(42) = 267914296

6 years ago

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surrounded matrix
With a given matrix A (size m x n) create a matrix B (size m+2 x n+2) so that the matrix A is surrounded by ones: A = [1 2 ...

6 years ago

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Back to basics 21 - Matrix replicating
Covering some basic topics I haven't seen elsewhere on Cody. Given an input matrix, generate an output matrix that consists o...

6 years ago

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Remove NaN ?
input -> matrix (n*m) with at least one element equal to NaN; output -> matrix(p*m), the same matrix where we deleted the enti...

6 years ago

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Golomb's self-describing sequence (based on Euler 341)
The Golomb's self-describing sequence {G(n)} is the only nondecreasing sequence of natural numbers such that n appears exactly G...

6 years ago

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Sum the Infinite Series
Given that 0 < x and x < 2*pi where x is in radians, write a function [c,s] = infinite_series(x); that returns with the...

6 years ago

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Find the stride of the longest skip sequence
We define a _skip sequence_ as a regularly-spaced list of integers such as might be generated by MATLAB's <http://www.mathworks....

6 years ago

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"Look and say" sequence
What's the next number in this sequence? * [0] * [1 0] * [1 1 1 0] * [3 1 1 0] * [1 3 2 1 1 0] This a variant on the w...

6 years ago

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Sum of first n terms of a harmonic progression
Given inputs a, d and n, return the sum of the first n terms of the harmonic progression a, a/(1+d), a/(1+2d), a/(1+3d),....

6 years ago

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Square Digits Number Chain Terminal Value (Inspired by Project Euler Problem 92)
Given a number _n_, return the terminal value of the number chain formed by summing the square of the digits. According to the P...

6 years ago

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Integer sequence - 2 : Kolakoski sequence
Get the n-th term of <https://oeis.org/A000002 Kolakoski Sequence>.

6 years ago

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Alternating sum
Given vector x, calculate the alternating sum y = x(1) - x(2) + x(3) - x(4) + ...

6 years ago

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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 ...

6 years ago

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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...

6 years ago

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Integer Sequence - II : New Fibonacci
Crack the following Integer Sequence. (Hints : It has been obtained from original Fibonacci Sequence and all the terms are also ...

6 years ago

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Return fibonacci sequence do not use loop and condition
Calculate the nth Fibonacci number. Given n, return f where f = fib(n) and f(1) = 1, f(2) = 1, f(3) = 2, ... Examples: ...

6 years ago

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Find the next Fibonacci number
In the sequence of Fibonacci numbers, every number is the sum of the two preceding ones: 1, 1, 2, 3, 5, 8, 13, 21, 34, 55...

6 years ago

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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 ...

6 years ago

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Get all prime factors
List the prime factors for the input number, in decreasing order. List each factor. If the prime factor occurs twice, list it as...

6 years ago

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Find vampire numbers
A <http://en.wikipedia.org/wiki/Vampire_number vampire number> is a number v that is the product of two numbers x and y such th...

6 years ago

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Find all vampire fangs
A <http://en.wikipedia.org/wiki/Vampire_number vampire number> is a number v that is the product of two numbers x and y such th...

6 years ago

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Fangs of a vampire number
A <http://en.wikipedia.org/wiki/Vampire_number vampire number> is a number v that is the product of two numbers x and y such tha...

6 years ago

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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...

6 years ago

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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...

6 years ago

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Divisible by n, Composite Divisors
Pursuant to <http://www.mathworks.com/matlabcentral/cody/problems/42453-divisible-by-n-prime-vs-composite-divisors Divisible by ...

6 years ago

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Divisible by n, prime divisors from 20 to 200
Pursuant to the previous problem (linked below), this problem requires a function that checks for divisibility of large numbers ...

6 years ago

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Divisible by n, prime divisors - 11, 13, 17, & 19
Divisibility checks against prime numbers can all be accomplished with the same routine, applied recursively, consisting of add ...

6 years ago