#include <stdio.h>
 
int main(void) {
	int a[30];
    a[0] = 2;
    a[1] = -1;
 
    printf("a[0] = %d\n", a[0]);
    printf("a[1] = %d\n", a[1]);
 
    for (int i = 2; i < 30; i++) {
        a[i] = -a[i - 1] + a[i - 2] + 2;
        printf("a[%d] = %d\n", i, a[i]);
        if (a[i] > 5000) {
            printf("\n✅ 初めて5000を超えるのは %d 項目（0始まり）\n", i);
            printf("   ➤ 値は %d です\n", a[i]);
            break;
        }
    }
	return 0;
}
 

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