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  1. #include <stdio.h>
  2.  
  3. int isPrime(int n) {
  4.     if (n < 2) return 0;
  5.     for (int i = 2; i * i <= n; i++) {
  6.         if (n % i == 0) return 0;
  7.     }
  8.     return 1;
  9. }
  10.  
  11. int main(void) {
  12.     int a[33]; 
  13.     int count = 0; 
  14.  
  15.  
  16.     a[0] = 2;
  17.     a[1] = -1;
  18.  
  19.  
  20.     for (int i = 2; i <= 32; i++) {
  21.         a[i] = -a[i - 1] + a[i - 2];
  22.     }
  23.  
  24.  
  25.     for (int i = 0; i <= 32; i++) {
  26.         if (a[i] > 0 && isPrime(a[i])) {
  27.             count++;
  28.         }
  29.     }
  30.  
  31.  
  32.     printf("正で素数の個数は %d 個です。\n", count);
  33.  
  34.     return 0;
  35. }
  36.  
Success #stdin #stdout 0s 5308KB
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正で素数の個数は 5 個です。
https://ideone.com/tMHXOn
language:
C (gcc 8.3)
created:
9 days ago
visibility:
public

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