Question

帕多瓦数列：1,1,1,2,2,3,4,5,7,9,12,16,21 求这个数列的前20项的和 用c语言程序

Answer 1

#include<stdio.h>
#define MAX 50
void main()
{
int i;
int sum = 0;
int a[MAX] = {1, 1, 1};
for ( i=3; i<20; i++)
{
a[i] = a[i-3]+a[i-2];
}
for ( i=0; i<20; i++)
{
sum += a[i];
printf("%d ",a[i]);
}
printf("\n前20项和为:%d\n",sum);
}

Answer 2

#include "stdio.h"
void main() //递归算法
{
int k,sum=0;
for( k=1;k<21;k++)
{
printf("%d ",Foo(k));
sum+= Foo(k);
}
printf("\n前20项和为:%d\n",sum);
}
int Foo(int i)
{
if (i <= 3)
return 1;
else return Foo(i -3) + Foo(i - 2);
}