#include <stdio.h>
int a(int n){
if(n==1){
return 1;
}else{
return 2*a(n-1)+2;
}
}
int main(void) {
int n;
printf("a(%d)の値は%d\n", n
, a
(n
)); return 0;
}
I2luY2x1ZGUgPHN0ZGlvLmg+CgppbnQgYShpbnQgbil7CiAgICBpZihuPT0xKXsKICAgICAgIHJldHVybiAxOwogICAgfWVsc2V7CiAgICAgICByZXR1cm4gMiphKG4tMSkrMjsKICAgIH0KfQoKaW50IG1haW4odm9pZCkgewogICAgaW50IG47CgogICAgc2NhbmYoIiVkIiwgJm4pOwogICAgcHJpbnRmKCJhKCVkKeOBruWApOOBryVkXG4iLCBuLCBhKG4pKTsKICAgIHJldHVybiAwOwp9Cg==