Solved

2 years ago

Solved

Play Outside In with primes
In the word game Outside In,* you start with a word, take the first and last letters, try to think of a word in which the two le...

2 years ago

Solved

Count the primes in Collatz sequences
Several Cody problems (21, 69, 42937, 44448, 44784, 52422) involve Collatz sequences. These start with a seed . If is odd, the ...

2 years ago

Solved

Determine whether a number is unprimeable
The number 204 is unprimeable because no single digit can be changed to make it prime. In contrast, the number 207 is not unprim...

2 years ago

Solved

List prime anagrams of a number

2 years ago

Solved

Find the smallest prime with n inside
Consider the sequence that begins 101, 113, 127, 131, 149, 151, 163,... Not only is every term prime, the th term is the smalles...

2 years ago

Solved

List the nth prime quartet prefix
Prime numbers larger than 5 can end only in 1, 3, 7, or 9, but of course not all numbers ending in these four digits are prime. ...

2 years ago

Solved

List Honaker primes
The number 131 is the 32nd prime number. It is a Honaker prime because the sum of its digits (1+3+1) equals the sum of the digit...

2 years ago

Solved

Label primes with the Erdos-Selfridge classification

2 years ago

Solved

List Proth primes

2 years ago

Solved

Compute home primes in a given base

2 years ago

Solved

Determine whether a number is a prime self number
Integers can be classified as generated numbers or self numbers. A generated number is one that can be expressed as the sum of a...

2 years ago

Solved

List the good primes
The th prime is classified as “good” if for . For example, 5 is a good prime because is greater than and , but 7 is not beca...

2 years ago

Solved

List the dihedral primes
The number 1880111 is a dihedral prime (or dihedral calculator prime) because on a seven-segment display it is prime (a) forward...

2 years ago

Solved

List the delete-a-digit primes

2 years ago

Solved

Play PRIMEGAME
Have you ever used the Sieve of Eratosthenes and said, "I wonder whether there’s a less efficient way to find prime numbers."? N...

2 years ago

Solved

Create a sequence of primes p such that p > n π(p)

2 years ago

Solved

Test approximations of the prime counting function

2 years ago

Solved

Find jumping medalists

2 years ago

Solved

Construct a prime circle
A <https://mathworld.wolfram.com/PrimeCircle.html prime circle> is a circular arrangement of the numbers 1 to 2n such that pairs...

2 years ago

Solved

Test the generalized Legendre conjecture

2 years ago

Solved

Determine digits of the Copeland-Erdos constant
<https://www.mathworks.com/matlabcentral/cody/problems/1477-champernowne-constant/solutions/new Cody Problem 1477> asks us to de...

2 years ago

Solved

Investigate the frequency of last non-zero digits of primorials

2 years ago

Solved

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...

2 years ago

Solved

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 ...

2 years ago

Solved

Identify primorial primes
Cody Problems <https://www.mathworks.com/matlabcentral/cody/problems/46054-count-trailing-zeros-in-a-primorial 46054> and <https...

2 years ago

Solved

Identify full reptend primes

2 years ago

Solved

Identify Wagstaff primes
The numbers 3, 43, and 2731 are examples of <https://mathworld.wolfram.com/WagstaffPrime.html Wagstaff primes>. Write a func...

2 years ago

Solved

Determine whether a number is a cluster prime
A <https://mathworld.wolfram.com/ClusterPrime.html cluster prime> is an odd prime number _p_ such that all even numbers less tha...

2 years ago

Solved

Investigate the frequency of last digits of prime numbers
The last digit of a prime number greater than 5 can be 1, 3, 7, or 9. If the primes are distributed randomly, then these digits ...

2 years ago