C语言数列 问题，求数列的 前20项

Question

设有一个数列,它的前四项为0,0,2,5，以后每项分别是其前四项之和，编程求此数列的前20项 C语言

Answer 1

#include <stdio.h>
int main()
{
    int a = 0, b = 0, c = 2, d = 5;
    int t, sum = 7;
    int i = 5;
    for (; i <= 20; i++)
    {
        t = a + b + c + d;
        a = b;
        b = c;
        c = d;
        d = t;
        sum += t;
    }
    printf("%d", sum);
    return 0;
}