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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...

1 year 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 ...

1 year 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 year ago

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

1 year 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 year 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 year 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 year ago

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First N Perfect Squares
*Description* Return the first N perfect squares *Example* input = 4; output = [ 1 4 9 16 ];

1 year ago

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find nth even fibonacci number
1st even fibonacci number=2 ; 2nd even fibonacci number=8 ..

1 year ago

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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...

1 year 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 year ago

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Lychrel Number Test (Inspired by Project Euler Problem 55)
The task for this problem is to create a function that takes a number _n_ and tests if it might be a Lychrel number. This is, re...

1 year ago

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Iccanobif numbers 1
There are a lot of problems in Cody that deal with Fibonacci numbers (1, 1, 2, 3, 5, 8, 13, 21 etc...) so let's turn things arou...

1 year ago

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Pentagonal Numbers
Your function will receive a lower and upper bound. It should return all pentagonal numbers within that inclusive range in ascen...

1 year ago

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Extra safe primes
Did you know that the number 5 is the first safe prime? A safe prime is a prime number that can be expressed as 2p+1, where p is...

1 year 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 year 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 year ago

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Pell numbers
Find the nth pell number <https://en.wikipedia.org/wiki/Pell_number>

1 year ago

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generate nth pentatope number
https://en.wikipedia.org/wiki/Pentatope_number

1 year ago

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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...

1 year 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 year ago

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P-smooth numbers
This Challenge is to find <https://en.wikipedia.org/wiki/Smooth_number P-smooth number> partial sets given P and a max series va...

1 year ago

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Champernowne Constant
The <http://en.wikipedia.org/wiki/Champernowne_constant Champernowne constant> is a real number whose digits in decimal represen...

1 year 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 year ago

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Last non-zero digit
Given a number n, find the last non-zero digit of the factorial of that number. You need to take care of the large values of n....

1 year ago

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Determine if input is a Narcissistic number
<http://en.wikipedia.org/wiki/Narcissistic_number Narcissistic number> is a number that is the sum of its own digits each raised...

1 year ago

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Circular Primes (based on Project Euler, problem 35)
The number, 197, is called a circular prime because all rotations of the digits: 197, 971, and 719, are themselves prime. The...

1 year 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 year ago

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Amicable numbers
Test whether two numbers are <https://en.wikipedia.org/wiki/Amicable_numbers amicable>, meaning that the sum of the proper divis...

1 year ago

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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...

1 year ago