#include <stdio.h>
//a{n} = -6a{n-1} -9a{n-2}, a{1}=1, a{2}=2(再帰あり版)
int static count=0;
int rec(int n){
	count++;
	if(n==1){
		return 1;
	}
else if(n==2){
	return 2;
}
else {
	return -6*rec(n-1)-9*rec(n-2);
}
}
 
int main(void) {
    int n = 5;
    printf("数列a%dの値は%d\n", n
, rec
(n
));     printf("この時のrecの呼び出し回数は%d回です",count 
); 	return 0;
}
 
 
				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