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Kaprekar numbers
Test if the input is a Kaprekar number: <http://mathworld.wolfram.com/KaprekarNumber.html>. Return a logical true or false. ...

1 month ago

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Narcissistic number ?
Inspired by Problem 2056 created by Ted. In recreational number theory, a narcissistic number is a number that is the sum of ...

1 month ago

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Polygonal numbers
The task of <http://www.mathworks.co.uk/matlabcentral/cody/problems/5 Problem 5> is to calculate triangular numbers. By playing ...

1 month ago

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Polite numbers. N-th polite number.
A polite number is an integer that sums of at least two consecutive positive integers. For example _7 = 3+4_ so 7 is a polite...

1 month ago

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Polite numbers. Politeness.
A polite number is an integer that sums of two or more consecutive positive integers. Politeness of a positive integer is a num...

1 month ago

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Evil Number
Check if a given natural number is evil or not. Read more at <https://oeis.org/A001969 OEIS>.

1 month 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

1 month ago

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N-th Odious
Given index n return n-th <https://oeis.org/A000069 odious number>.

1 month ago

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nth Rational Number
Return the nth rational number. This is the inverse to Problem 1471. Index of a Rational number The first ten positive rationa...

1 month ago

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Armstrong Number
Determine whether the given input n-digit number is Armstrong Number or not. Return True if it is an Armstrong Number. An n-Dig...

1 month ago

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Generate a Parasitic Number
This problem is the next step up from Problem 156. Rather than determining if an input is a parasitic number, you will be asked ...

1 month ago

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Is this number Munchhausen?
In this problem, simply return 1 if a supplied number is Munchhausen or 0 if not. Example 153 is narcissistic but not a Munchh...

1 month ago

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Bell Number calculator
Calculate a vector of Bell numbers for sets up to length n. Bell numbers are the maximum number of partitions of a set. See the ...

1 month ago

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Find the 9's Complement
Find the 9's complement of the given number. An example of how this works is <http://electrical4u.com/9s-complement-and-10s-c...

1 month ago

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Sort numbers by outside digits
Sort the array so that they are sorted as if their value was a 5 digit number made from the first three and last two digits of t...

1 month ago

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Index of a Rational number
The set of real numbers are infinite. They are so many that real numbers can't even be enumerated. However, unlike real numbers ...

1 month ago

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Tridiagonal
Return an n-by-n matrix that has a, b, c as the subdiagonal, main diagonal, and superdiagonal entries in the matrix. Example ...

1 month ago

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Index one element in each vector of an array along a given dimension
Functions like min and max can return in their second output argument the index of the element in each vector along a particular...

1 month ago

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Find the maximum two numbers of every column of a matrix
Find the maximum two numbers of every column of a matrix. Example: If we input a matrix A = [ 1 2 4 6 0 3 ...

1 month ago

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Finding neighbors of [-1:1] in a matrix....
Hello All! Well I found this one fun to figure out, all you have to do is make a matrix of 1's or 0's (true or false) that sh...

1 month ago

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How unique?
Sometimes, when we check unique entries of vector we would like to know how many times each value occurs. Given vector of num...

1 month ago

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Another colon problem
This is simple problem based on problems 555, 801, 1118, etc. Create an index vector from two input vectors. Example: ...

1 month ago

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Sum of odd numbers in a matrix
Find the sum of all the odd numbers in a matrix. Example x = [2 3 5 7 1 4 11] y = 27

1 month ago

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Find the index of n in magic(n)
If input n=5, then magic(n) is 17 24 1 8 15 23 5 7 14 16 4 6 13 20 22...

1 month ago

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Replace pattern 0 1 0 and 1 0 1
Find and replace a pattern in a row of zeroes and ones. * Find 1 0 1 and replace it with 1 1 1 * Find 0 1 0 and replace it w...

1 month ago

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Largest territory
Determine whose territory is largest. If there are multiple numbers tied for the largest territory, return the smallest number. ...

1 month ago

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counting groups!
This problem is about counting groups. Example If you have x: x = [0.8 0.8 0.8 0.3 0.3 0.4 0.5 0.6 0.6 0.9] then a...

1 month ago

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Three...is a magic number.
Yes it is... It's a magic number... To help you get rid of that earworm, here's a new Cody problem. You are given a squar...

1 month ago

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Time Expansion
How can you slow down any discrete-time signal? Example Input original signal x. x = [1 2 3 -1 -2 -5 -4] We want t...

1 month ago

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Back to basics - mean of corner elements of a matrix
Calculate the mean of corner elements of a matrix. e.g. a=[1 2 3; 4 5 6; 7 8 9;] Mean = (1+3+7+9)/4 = 5

1 month ago