C Exercises: Display first 10 Fermat numbers

Last update on August 05 2025 12:55:54 (UTC/GMT +8 hours)

30. Fermat Numbers Variants

Write a program in C to display the first 10 Fermat numbers.

Sample Solution:

C Code:

# include <stdio.h>
# include <stdlib.h>
# include <math.h>

int main()
{
    int n = 0; // Variable 'n' initialized to 0 to track the iteration count
    double result; // Variable to store the calculated Fermat number

    printf("\n\n Display first 10 Fermat numbers:\n");
    printf("-------------------------------------\n");
    printf(" The first 10 Fermat numbers are: \n");

    // Loop to calculate and display the first 10 Fermat numbers
    while (n <= 10) 
    {
        result = pow(2, pow(2, n)) + 1; // Calculating the nth Fermat number using the formula 2^(2^n) + 1
        n++; // Incrementing 'n' for the next iteration

        printf("%lf \n", result); // Printing the calculated Fermat number
    }
}

Sample Output:

 The first 10 Fermat numbers are:                                                                             
3.000000                                                                                                      
5.000000                                                                                                      
17.000000                                                                                                     
257.000000                                                                                                    
65537.000000                                                                                                  
4294967297.000000                                                                                             
18446744073709551616.000000                                                                                   
340282366920938463463374607431768211456.000000                                                                
115792089237316195423570985008687907853269984665640564039457584007913129639936.000000                         
13407807929942597099574024998205846127479365820592393377723561443721764030073546976801874298166903427690031858
186486050853753882811946569946433649006084096.000000                                                          
inf

Visual Presentation:

C programming: Display first 10 Fermat numbers.

Flowchart:

For more Practice: Solve these Related Problems:

Write a C program to generate Fermat numbers using iterative exponentiation.
Write a C program to verify Fermat numbers with large integer arithmetic libraries.
Write a C program to compute Fermat numbers and check the primality of each number.
Write a C program to display Fermat numbers in scientific notation for extremely large outputs.

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